Free the terminal from the Hosts screen, and fill the room it left

The WebView sat inside the Hosts grid, so navigating to Files or the keychain
hid every open terminal and the strip that named them. A connection you had
opened was invisible from four of the five screens. The window now has two
surfaces rather than one: a nav rail that says which page you are on, and a
terminal strip that is always there and switches the whole content area to a
shell. Screen keeps meaning "which page" and never becomes a sixth kind of
page, which is why this is two properties instead of one enum with a terminal
member in it.

Every screen lives inside one wrapper panel that collapses when a terminal is
showing. That is not tidiness — the WebView hosts a Win32 child window that
composites above everything Avalonia draws, so a screen left visible over its
rectangle is a screen sliced in half, and this window has shipped that defect
once already. One decision point, IsTerminalShowing, and a nested panel rather
than five compound bindings nobody would remember to extend.

The focus choreography is the part no test in this repo can see. Every reveal
path now focuses in the same turn the WebView appeared, so all three of them
post at DispatcherPriority.Loaded and let the native control re-push its bounds
first. Going the other way had a real bug: the screen-changed branch called a
bare Focus() where it had to release the keyboard from the native child, so
switching from a terminal to Files silently ate the first keystrokes. Rare
before this commit and the primary gesture after it.

The tab strip grew a cross inside each tab, a plus that opens the quick-connect
palette, and middle-click close. Nested buttons are correct here: Avalonia
handles a left press on the cross and deliberately does not handle other
buttons, which is exactly what lets middle-click bubble up from the cross as
well as the tab. The test is PointerUpdateKind rather than
IsMiddleButtonPressed, because the latter reports button state and is also true
for a left press made while the middle button happens to be held. The handler
is on the tab and not the strip, so the background closes nothing by
construction. Plus opens the palette rather than a flyout, since a menu
dropping into the WebView's rectangle may or may not composite above a child
HWND and this repo does not make rendering claims it has not photographed.

Everything a user reads now says keychain. The wire, the database and the
cryptographic spec still say vault, deliberately: renaming those is a migration
and a protocol change for a word. That split is written down rather than left
to be rediscovered as an inconsistency.

Four things that were squeezed into the keychain's category rail, or into
nothing at all, now have screens. Pinned host keys get one, with fingerprints
never truncated and a filter that matches them, because comparing what you have
against what the operator published is the whole workflow; the approved date is
read out of the item's UUIDv7 rather than added as a column, and says so, since
it means first approval and not last use. Keys can be generated in the client,
which needed the openssh-key-v1 container written by hand — there is no BCL or
NSec helper, and the PKCS#8 route is unverified in the SSH library this uses.
The armour carries no passphrase: encrypting it needs bcrypt_pbkdf, which is
Blowfish with a swizzle, in a project whose crypto is otherwise entirely
libsodium, for a protection the key's own remarks argue is redundant inside a
vault. Generation fills the existing editor and stops, so SAVE stays the one
thing that writes. ~/.ssh/config can be imported behind a preview that is
ticked per row and writes nothing until the button; IdentityFile records the
path and imports the key material only on an explicit opt-in, because reading
somebody's private key into a vault is precisely the act this product exists to
make deliberate. Match blocks and ProxyJump are reported rather than obeyed —
one cannot be evaluated statically and the other has nothing behind it to route
with, and a preview that implied otherwise would be worse than one that admits
it.

Files can be dragged in all four directions that are honestly available. Remote
to Explorer does not ship and is not pretended to: the shell wants the bytes
during the drop, which needs a virtual file and a native COM data object,
outside what Avalonia offers. Note for the next person that Avalonia 12
replaced the drag model outright — DataObject and DataFormats are no-op stubs
and IDataObject is not in the reference assembly, so every tutorial written for
11 does not compile here.

Hosts can be grouped, flat and never nested. A parent id merged as a scalar
lets two offline clients each re-parent A under B and B under A, producing a
cycle inside an encrypted payload that no server can police and every reader
would have to detect for ever. Membership lives in that payload rather than in
the one plaintext concession ADR 0001 allows, whose test is that the relay
cannot function without it — nothing on the server reads a group, so what
plaintext would hand over is a clustering of the estate for nothing. The
plaintext column reserved for it is dropped, provably always null, and the
server now refuses a client that sends one; it was never populated, was copied
on apply, and was not cleared on delete, so a group id would have outlived the
host it described.

Snippets insert through xterm rather than through the pump, because xterm is
the only thing that knows whether the remote has bracketed paste on, and that
is what makes a shell treat embedded newlines as text instead of as execute.
The host process moves opaque bytes and never parses output, so it would have
to guess, and guessing wrong runs every line. Running is off by default and the
copy says the text goes into whatever is there — the terminal has no notion of
being at a prompt, and may be in vi or at a password prompt with echo off, so
the Enter the user presses themselves is the entire safety property.

Connections and keychain changes are recorded as synced encrypted items, which
is what makes them auditable by a team later and costs the server knowledge of
connection rate and timing from row counts alone. ADR 0001 already concedes it
cannot hide that class of metadata; the trade is now written into it rather
than left implicit. A connection entry is written once, at close, which is what
makes a synced log tractable: nothing to merge, one outbox row, no chance of
colliding with itself. Live sessions come from memory, not from the log. The
write is void by contract and posts to a bounded channel, because putting an
encrypt-and-write on the teardown path of every session is how closing the
application comes to take four seconds. A ticket opened before a lock still
closes afterwards, since a shell outlives the vault. The activity log hooks the
one generic repository every kind writes through, so it cannot miss a caller —
which is also why the log kinds themselves declare they are not audited, or the
first entry would write an entry about writing an entry. It records the names
of the fields that changed and never their values; a log with an old password
in it would be a plaintext credential store with no vault around it. Retention
is 90 days or 5,000 entries, whichever bites first, pruned on the sync loop
rather than on a second timer.

That log traffic then broke the status line, which is worth recording because
the fix is a shape and not a patch: background sync counted its own log rows as
pushed items, so the quiet rule stopped being quiet and every action's message
was overwritten a second later by a sync report. The report now separates log
rows from user items and the rule reads the latter.

S3 buckets appear as a remote in the file browser, behind the same interface an
SFTP session implements, so the queue and both panes did not have to learn what
they are talking to. Uploads go through a pipe, because the queue wants to
write and the SDK wants to read; memory is then bounded by the part size
instead of buffering a file to disk twice.

Finally, the Windows device key store moved out of the session project, which
was the one thing keeping it from being portable — everything else in it is
platform-neutral, and a Windows CNG dependency in the middle of the vault code
meant a second head could not reference it without dragging Windows along. The
seam that made the move free was already there. docs/android-port.md is the
audit behind that: what ports, what does not, in order of cost, the four
decisions taken, and an inventory of every screen and state the interface has
to carry, written so a design can be made from it directly.

dotnet build, dotnet test and dotnet format --verify-no-changes are all clean:
1240 tests at zero warnings, including the end-to-end suite against real
containers. The manual checks that headless Avalonia cannot make — the drag
from Explorer, a generated key against a real host, twelve tabs at the minimum
window width — are listed in docs/manual-checks.md and are still outstanding.

docs/design-import-gaps.md

@@ -36,12 +36,72 @@ caller's own personal one. That removes the Teams screen entirely, and with it e
 cache has six tables, none of them settings. Nothing on the design's TERMINAL preferences panel can be
 saved, and there is no frame on the terminal data plane that would carry a change to the renderer anyway.
 
+**Three things the design did not ask for and this build now has.** A key can be generated in the client
+rather than pasted in (`SshKeyGenerator`, and the `openssh-key-v1` container is written by hand — see
+`OpenSshKeyWriter` for why there was no alternative and why it is written unencrypted). Hosts can be
+imported from `~/.ssh/config` (`DodoSSH.Client.Import`; it reads no key material, and `ProxyJump` is
+recorded as intent because the SSH layer still has no jump hosts). And the file-transfer screen takes drag
+and drop in four directions — remote to Explorer is the one that does not ship, because it needs a virtual
+file the platform layer cannot supply; see `docs/manual-checks.md`.
+
+**The rail has six destinations, not five.** The design gives host keys no slot at all. They were a fourth
+category on the keychain screen for a while and are now a screen of their own, `KnownHostsScreen`, because
+the other categories are things somebody creates and edits and a pin is a decision recorded at the moment
+of connecting — and because comparing an untruncated fingerprint against a published one needs a column
+layout the shared table could not give it.
+
+**The product surface says "keychain" and everything under it says "vault", deliberately.** The nav rail,
+the unlock and enrollment copy, and every sentence a user reads now call the encrypted store a keychain.
+The wire does not: the route is `/api/v1/vaults/{vaultId}`, the tables are `vault` and `vault_key_grant`,
+the CLR types are `VaultViewModel` and `VaultSession`, and `docs/crypto.md` — which is normative — says
+"vault key". Renaming those would break every deployed client, need a table-rename migration, and put
+`CryptoSpec.AadResourceType.Vault = 3` inside the blast radius of a find-and-replace, where changing it
+would make every item in every vault permanently unreadable. So the split is the answer rather than a
+stage on the way to one: read "vault" in this repository as the name of the cryptographic object, and
+"keychain" as what the product calls it.
+
 One thing cuts the other way and is worth knowing before planning any of this: **the wire protocol already
 reserves the slots**. `SyncEntityType` (`src/DodoSSH.Contracts/SyncEntityType.cs`) has `HostGroup = 4`,
 `Tag = 5`, `HostTag = 6`, `HostCredential = 7`, `Snippet = 8` and `PortForward = 9` — reserved, unused, and
 already covered by the AAD resource-type table. Groups, tags and snippets are new item types on an existing
 protocol rather than a protocol change.
 
+Two of those slots are now taken. `HostGroup` and `Snippet` shipped as full item kinds — a table, an EF
+configuration, a server kind that refuses every plaintext field, a codec, a merge, a cipher and a repository
+— and neither needed a contract change, which is what the reservation bought. `Tag`, `HostTag`,
+`HostCredential` and `PortForward` are still reserved and still unused.
+
+**A third was added for something the design never mentioned**: `ObjectStore = 13`, an S3-compatible bucket
+and the keys that reach it. It is a keychain item like any other — the endpoint and the secret access key are
+both inside the payload, and the server refuses every plaintext field including the endpoint, because for
+everybody self-hosting that is an address on their own network.
+
+What made it cheap is that the transfer queue never needed anything SSH-specific: `IRemoteFileStore` was
+lifted out of `ISftpSession` with only the host key left behind, and a bucket is the same contract with a
+different implementation. Three things a bucket genuinely cannot do are refused with a reason rather than
+approximated — there are no directories (only keys with slashes in them, and a marker object for an empty
+one), no resumable upload (an object cannot be written from the middle), and no atomic rename (a copy and a
+delete). Downloads *do* resume, because a ranged GET is part of the protocol.
+
+**Two members were added rather than claimed**: `ConnectionLogEntry = 11` and `ActivityLogEntry = 12`, the
+first additions to `SyncEntityType` since it was frozen. Logs are synced items rather than local files
+because they are audit records — an administrator has to be able to read a shared vault's history once teams
+land, and a log kept only on the machine that produced it can be neither read nor trusted by anybody else.
+ADR 0001 records what that costs in metadata; it is not free and it is not hidden.
+
+Three properties are worth knowing before touching them. An entry is **written once, at close** and never
+updated, which is what lets a synced log avoid a merge entirely. Neither kind is **audited**, which is the
+guard that stops the activity log producing an entry for every entry it writes. And both are **excluded from
+the pending-change count and from what a background sync announces** — those numbers answer "how much of my
+work is not yet safe", and a log entry is not somebody's work.
+
+**One plaintext field was taken away rather than used.** `SyncPlaintextFields.GroupId` has existed since the
+contract was frozen and `host.group_id` since the first migration; no client ever wrote either. Group
+membership is inside the encrypted payload instead, the column is dropped, and the server now refuses the
+field with a reason — because what it would have handed the operator is a clustering of every user's estate,
+and ADR 0004's test for a plaintext concession is that the server *cannot function* without it. The wire
+field cannot be removed and stays as a permanently refused member; `SyncEndpointTests` holds the refusal.
+
 ---
 
 ## Chrome — titlebar, nav rail, status bar
@@ -71,13 +131,13 @@ caption buttons and window title drawn on top of the application's own — two s
 | Design element | Layer | What it would take | What ships instead |
 | --- | --- | --- | --- |
 | Tag chips (`nginx`, `eu`, `pg16`) | client-domain | A tag item type and a host-tag join. Both reserved on the wire (`Tag = 5`, `HostTag = 6`), neither implemented, plus a payload schema bump on `HostSecret`. | Omitted. The filter box searches name, address and notes instead. |
-| Groups `PRODUCTION` / `STAGING` / `PERSONAL` | client-domain | A host-group item type (`HostGroup = 4`, reserved) or a group field on `HostSecret`. | One collapsible heading, named after the vault — the only grouping a host actually has. A second appears when a second vault becomes reachable. |
+| Groups `PRODUCTION` / `STAGING` / `PERSONAL` | client-domain | A host-group item type (`HostGroup = 4`, reserved) or a group field on `HostSecret`. | **Shipped**, as both: `VaultHostGroup` is a synced item kind and `HostSecret.GroupId` names one. Flat, not nested. A keychain with no groups renders exactly as it did before — one flat list, no headings. |
 | Group badge `TEAM·PLATFORM` | server | Teams. | Omitted. |
 | Per-host status dot, three colours | client-ssh | The amber state would mean "reachable but not connected", and nothing here ever probes a host. | Two states, both real: green when a terminal is open on that host, grey when not. |
 | `· ⤷ bastion-eu` in the host subtitle | client-ssh | **Jump hosts are data-only.** `HostSecret.JumpHostIds` is a `JumpChain` that is stored, encrypted, synced and three-way merged — and nothing reads it at connect time. `SshConnectionRequest` carries one host. | Omitted. The stored chain is preserved untouched by every edit. |
 | `SPLIT ⌘D` and side-by-side panes | client-ssh + ui | The renderer stacks panes and shows one (`terminal.css`: `.pane { position:absolute; inset:0; display:none }`). Tiling needs a real pane geometry and a splitter. | Omitted. Tabs ship instead, over the same one-WebView multiplexing. |
 | `⇄ FORWARDS · 2` | client-ssh | Port forwarding. `SyncEntityType.PortForward = 9` is reserved; nothing in the SSH layer forwards anything. | Omitted. |
-| `SNIPPETS` panel, `↵` to run | client-domain | A snippet item type (`Snippet = 8`, reserved). | Omitted. |
+| `SNIPPETS` panel, `↵` to run | client-domain | A snippet item type (`Snippet = 8`, reserved). | **Shipped**, as a screen rather than a panel. `↵` is per snippet and off by default: inserting types the command at the prompt and stops, because nothing here can tell whether the terminal is at a prompt at all. |
 | Broadcast to all panes (`⌥↵`) | client-ssh | Input is routed strictly by session id in `TerminalDataPlane.Dispatch`; there is no fan-out. Needs splits first. | Omitted. |
 | Pane header `24ms` | client-ssh | Round-trip measurement. SSH.NET offers no RTT API. | Omitted. |
 | Pane header `aes256-gcm` | client-ssh | **The closest miss on this list.** `SshNetConnection` holds the `SshClient`, so `ConnectionInfo.CurrentServerEncryption` is right there — it just is not on `ISshConnection` or surfaced by `TerminalWorkspace`. | Omitted; the tab strip shows the account and endpoint actually dialled. |