Merge remote-tracking branch 'origin/master' into codex/basic-session-search

Conflict resolutions:

- `session.list`: master's projection columns fold into the PR's cancellable,
  batched `listVisibleSessionSummaries`, which `session.search` shares as its
  visibility baseline; master's goal helpers stay beside it.
- Client sessions face: master narrowed `ctx.sessions` to `ISessions`, so the
  search verb and its protocol-constant bound are declared there and the
  test-runtime double implements them (recorded, empty page unless a scenario
  stubs hits).
- `WorkspaceBrowser`: master's per-row Rename wiring rides the PR's search
  results view; the tree keeps the PR's query-free derivations.
- `dsh web` bin: the PR's shutdown-handlers-before-readiness order with
  master's boot-time LAN address snapshot.
- `session-query-sqlite`: master's `SCHEMA_VERSION` 7 stands; the PR's bump
  carried no schema change.
- Specs: master wraps assistant/steering message payloads and requires an
  `application/json` carrier request, so the search fixtures and tests follow.
- Web aria goldens keep master's recording plus the PR's search placeholder;
  the navigation-panes inventory keeps master's terminal-card golden next to
  the PR's search-results golden.

packages/host/apiproxy/README.md

@@ -6,11 +6,13 @@ The API gateway every client shape shares: the TS contract (`src/api/`, zero Nod
 
 ## Contract layer (`/api`)
 
-Wire messages form a four-quadrant discriminated union — who initiates × request/response — decoupled from the physical channel: `ClientRequest` (POST `/api/<method>` body), `ServerResponse` (that POST's response body), `ServerRequest` (SSE frame), `ClientResponse` (POST `/api/respond` body). Responses always echo the matching request's `rpcId` and never mint a new one. Method parameter/return structures live only in the domain interface signatures (`SessionsApi`, `HostApi`, `EventsApi`); `RpcMethodMap` registers the methods and every other position derives via `RequestPayload<K>`/`ResponseValue<K>`. Zod schemas anchor `satisfies z.ZodType<Wire<T>>` and parse at two levels: envelope first, business payload second, dispatched per method. Business errors ride `RpcResult`'s error branch (`RpcErrorDetailsMap` closes the code set); HTTP status expresses only the carrier.
+Wire messages form a four-quadrant discriminated union — who initiates × request/response — decoupled from the physical channel: `ClientRequest` (POST `/api/<method>` body), `ServerResponse` (that POST's response body), `ServerRequest` (SSE frame), `ClientResponse` (POST `/api/respond` body). Responses always echo the matching request's `rpcId` and never mint a new one. Method parameter/return structures live only in the domain interface signatures (`SessionsApi`, `HostApi`, `EventsApi`); `RpcMethodMap` registers the methods and every other position derives via `RequestPayload<K>`/`ResponseValue<K>`. Zod schemas anchor `satisfies z.ZodType<Wire<T>>` and parse at two levels: envelope first, business payload second, dispatched per method. Business errors ride `RpcResult`'s error branch (`RpcErrorDetailsMap` closes the code set); HTTP status expresses only the carrier. Every `/api` POST must declare the `application/json` media type — anything else is refused with 415 before dispatch, so cross-site "simple" requests (which browsers send without a CORS preflight) can never execute a side-effectful method blind.
 
 The layering/protocol decisions are recorded in the [GUI layering and RPC protocol RFC](../../../.agents/notes/implemented/architecture/2026-07-19-gui-layering-and-rpc-protocol.md); the browser-side consumption architecture in the [web client architecture RFC](../../../.agents/notes/implemented/architecture/2026-07-19-gui-web-client-architecture.md).
 
-The mux stream projects the latest log-backed title as a validated `session/title` control frame after each attached-session subscription baseline and immediately after the corresponding live raw title event. This projection does not add titles to `session.list`; cold sessions remain metadata-only there until opening or resuming attaches their logs.
+`session.history`'s tail page (`beforeSeq` absent) additionally carries an optional `projections` block — the watermark snapshot of every unit registered on `ctx.sessionProjections` (`@deepseek-ai/dsh-session-projection`), with `asOfSeq` = the last event seq the values reflect (`-1` on an empty log). The gateway also subscribes to the registry's change feed and mints a `session/projection` mux frame per changed unit (`{sessionId, key, value, seq}` — live push state, never logged; clients hold one generic per-session value store under higher-seq-wins). The carrier holds zero domain knowledge (each value passed its unit's own schema inside the registry; the wire schemas keep `values`/`value` wide); loadOlder pages never carry the block, and a composition without the registry serves histories without either surface.
+
+Session titles ride the generic projection pair like every other domain — the history-tail `projections` block plus `session/projection` frames under the `title` key (the bespoke `session/title` frame is retired). Titles do not join `session.list`; cold sessions remain metadata-only there until opening or resuming attaches their logs. `session.rename` accepts an explicit user title (resuming a cold session first), delegating to `ctx.sessionTitle.rename` — the accepted `session/title` event pins the title against automatic regeneration — and returns the normalized title plus its event seq so a client settles its `title` projection cell ahead of the push frame; a title that normalizes to empty returns `title-invalid`.
 
 Session model routing is a session-domain contract. `session.models` returns the selected provider/model/reasoning target with provider-grouped advisory models, exact-route reasoning metadata, and provider-local lookup failures. `session.selectModel` validates the optional adapter-owned reasoning effort and replaces the complete target selected for the next prompt-assembly boundary. Catalog membership is not validation: an adapter may resolve an unlisted model, while an unavailable route or unsupported effort returns `model-unavailable`.
 
@@ -20,11 +22,11 @@ Workspace and Session lists are separate reconnect baselines. `workspace.create`
 
 A stale continuation discards every partial result, deduplication entry, and cursor from that provider attempt, then restarts at the first page against the original list-derived visibility snapshot without discarding the learned provider page size. Limit probes and stale retries share the same limit of at most 100 provider calls (and therefore at most 2,000 inspected hits); a page larger than its requested limit, a repeated continuation cursor, or a still-unexhausted stream at that call budget fails closed as an `internal` business error. The carrier request signal cancels persistence listing, cold-summary collection, and every search call, including a limit or stale rejection observed concurrently with cancellation. A deployment without the service, or any unrecovered index/query failure, also returns an `internal` business error so clients can retain metadata-only matches.
 
-`host.pickDirectory` opens one native directory picker and returns its selected path, or `null` when the user cancels. Its host implementation invokes platform tools without a shell: `osascript` on macOS, an STA PowerShell `FolderBrowserDialog` on Windows, and Zenity with a KDialog fallback on Linux. The picker function is injectable for tests. This user-paced method is the sole unary call exempt from the default 30-second timeout; caller and connection aborts still propagate to the native process. The browser carrier separately restricts this privileged method to loopback, same-origin requests.
+Directory picking delegates to the composed `ctx.directoryPicker` backend ([the directory-picker seam](../directory-picker/README.md)); a method called outside the composed capability's kind fails with `directory-picker-unavailable` (the client needs no advertisement — the composed picker package's own client half renders the matching interaction). Under `native`, `host.pickDirectory` opens one native chooser and returns its selected path (`null` on cancel); this user-paced method is the sole unary call exempt from the default 30-second timeout, and caller/connection aborts still propagate to the native process. Under `browse`, `host.listDirectory` returns one name-sorted directory level with breadcrumb ancestry, a `home` anchor, and host-owned `hidden` flags (absent path = home directory), and `host.createDirectory` creates one validated child segment; the backend's typed failures map 1:1 onto the `directory-unreadable`/`directory-exists`/`directory-create-failed` codes. The browser carrier's prefix-wide trust fence (dsh-client-connection) covers all of these like every other `/api` request.
 
-`session.history` pages on message boundaries, and its tail page (no `beforeSeq`) carries two session-level extras the page window cannot supply: the in-flight partial's chunk events, and `todos` — the latest `todo/write` whole-list projection over the full log. Older pages omit `todos` because the projection is session-level, not per-page; a tail response that omits it means the whole log holds no `todo/write`, so clients read the absent field as the empty plan rather than as unchanged state.
+`host.openPath` opens a filesystem path with the operating system's default application (`open` on macOS, `Invoke-Item` on Windows, `xdg-open` on Linux). The opener is injectable for tests. The browser carrier applies the same loopback, same-origin restriction as `host.pickDirectory`.
 
-The `command.*` and `skill.*` domains expose the host command registry and skill catalog to clients. Every method addresses one session's agent by `sessionId` (a served session always has an Agent; `command.*` resumes cold sessions through the same path as `session.*`, while `skill.list` resolves the project root from the session header without touching the Agent registry). `command.execute` runs a slash-command line host-side and returns a detached result; the carrier's request signal cancels the running handler. `host/commands-changed` is the catalog invalidation frame: clients refetch `command.list` instead of diffing.
+The `command.*` and `skill.*` domains expose the host command registry and skill catalog to clients. Every method addresses one session's agent by `sessionId` (a served session always has an Agent; `command.*` resumes cold sessions through the same path as `session.*`, while `skill.list` resolves the project root from the session header without touching the Agent registry). `skill.list` serves the browser's user-selected model-reference path, so it returns only skills that are both model-invocable and user-invocable; this domain has no direct skill-loading RPC. `command.execute` runs a slash-command line host-side with pure admission semantics: the response reports whether the line resolved to a handler plus the minted lifecycle `commandId` when it did (correlating the acknowledgment with the flow node), while the outcome rides the durably logged `command/run`/`command/done` lifecycle pair broadcast on the mux stream; the carrier's request signal cancels the running handler. `host/commands-changed` is the catalog invalidation frame: clients refetch `command.list` instead of diffing.
 
 ## Carrier layer (`/client` + root)
 
@@ -44,4 +46,4 @@ None; this package neither assembles nor sends a provider request.
 - **Reserved seams stay out of `RpcMethodMap`** — `session.fork`, `prompt.mode: 'inject'`, `task.list`, `host.listModels`, and a describe `hostInstanceId` are documented reservations; an unknown method fails loud at envelope parse rather than getting a not-implemented code.
 - **No protocol version field** — client and host ship together; `host.describe` gains a version negotiation field only when an independently released client exists.
 - **Search failures include provider diagnostics** — the gateway is a single-user local service. A carrier that exposes it to multiple users must replace internal search details with a public-safe diagnostic.
-- **Linux native picker requires desktop tooling** — `host.pickDirectory` reports an actionable error when neither Zenity nor KDialog is installed; it does not fall back to a custom or typed-path browser.
+- **Linux native picker requires desktop tooling** — under the `native` capability, `host.pickDirectory` reports an actionable error when neither Zenity nor KDialog is installed; the browse backend is the composition-level fallback (see the [native backend README](../directory-picker-native/README.md)).