feat(dictation): add persistent language selection in General settings

docs/development.md

@@ -165,7 +165,7 @@ pricing-generation step: Pi AI's catalog and public calculator are the authority
 
 **Practice (problem sets).** A node selection resolves to the STORED reasoning chains it fully contains (a chain rides iff every member is selected; unchained nodes ride as singletons); the `/practice` creation dialog picks a birth-session cluster (the graph view's own groups) and freezes its propositions + chains into a self-contained `ProblemSet`. Three named-level axes steer generation (ladder rung 0–4, cue distance 0–2, Theory|Application — never a number to interpolate; defaults Direct exercise · Adjacent context · Theory), plus an optional free-form note the agents weigh but need not follow. Creation has two entries: the cluster picker on `/practice`, or the graph view's chain table — a full-bleed sortable table of every reasoning chain, grouped by birth cluster under the shared top bar, selecting chips, chains, or whole clusters, whose floating selection bar shows the exact `N nodes → M chains` the agents will receive — handing a free-form node selection to the same dialog — and carries the fenced Delete action, making it the graph's management view (whole-cluster cleanup through the same full-death confirm dialog). A partitioner agent covers every chain exactly once, one generator per partition writes problems against the owner's problem-engineering framework (commit-before-pose: statement + solution + rubric together), and grading is **strengthening, not assessment** — one attempt per problem with its own submit button, instant solution/rubric reveal, then a score 0–10 with brief reasoning landing live; nothing ever written back to the graph. Runs are registry-backed background jobs on the activity dock (no steer, never wakes the teacher); sets live in `data/practice`, crash-swept on boot.
 
-**Dictation.** Optional speech-to-text: the server mints short-lived Deepgram tokens; audio streams browser→Deepgram over WebSocket, never through the server.
+**Dictation.** Optional speech-to-text: the server mints short-lived Deepgram tokens; audio streams browser→Deepgram over WebSocket, never through the server. Settings → General → Dictation → Language offers Nova-3's documented monolingual languages/locales or `language=multi` for automatic multilingual transcription. The app-wide `dictation.language` preference persists through the existing settings record and `PUT /api/settings/dictation`; absent preferences resolve to English (`en`). The settings control locks from connecting through stopping, and reconnects keep the run's original language. A shared preference controller publishes confirmed PUT responses to every reader immediately; subsequent read failures cannot revert a confirmed choice. External settings notifications invalidate the cache, and capture waits for a successful refresh. Navigating away cancels the run, invalidates pending startup/reconnect work and releases its microphone/socket without appending into another page's input. All other streaming parameters remain unchanged. The picker composes the shared Button, Input, Hint and MenuShell with the existing `cmdk` dependency for accessible list navigation, using the app's fuzzy-search scoring.
 
 ## Testing
 
@@ -185,4 +185,4 @@ The teaching methodology comes from an Obsidian-based POC (its `knowledge graph
 
 Nothing under `data/` is ever tracked by git. Chats, graph ledgers, jobs, positions, and the settings records are plain files (JSON/JSONL) — inspect them freely; they are the canonical records. The desktop app relocates the whole directory via `LH_DATA_DIR`.
 
-**Schema stamps (2026-10-10):** chat records carry `version` (stamped at the store's write choke point; absence reads as v1 — lazy migration, no mass rewrite), and the graph family (ledgers, sources, render-settings) shares one sidecar `graph/format.json`, created on the family's first write. `positions.json` is deliberately unstamped (rebuildable). A record stamped NEWER than the running build is refused on read — honest refusal for the downgrade scenario: a read-modify-write store never rewrites what it doesn't understand.
+**Schema stamps (2026-10-10):** chat records carry `version` (stamped at the store's write choke point; absence reads as v1 — lazy migration, no mass rewrite), and the graph family (ledgers, sources, render-settings) shares one sidecar `graph/format.json`, created on the family's first write. `positions.json` is deliberately unstamped (rebuildable). A record stamped NEWER than the running build is refused on read — honest refusal for the downgrade scenario: a read-modify-write store never rewrites what it doesn't understand.