feat: right-click menus everywhere, workspace/session cost, long-term DB safety

Right-click menus: one portal shell (components/ContextMenu.tsx) for every
item with actions - sidebar/Recents/archived session rows (SessionMenu),
console tabs, pane headers, the Changes panel's files/tree/commits, the
workspace home, sessions outside a workspace (SessionRowMenu: Sessions
table, Dashboard, Activity, Workflow runs), prompt images, every Settings
list and every Claude Code/Codex config list (FileItemMenu). Buttons stay;
a delete keeps its button's confirm; the shell stops portal clicks from
reaching the card that opened it.

Status bar: Workspace $ and Session $ on the Workspace page, from
?lane= on GET /api/pricing/cost and the focused/replayed session's cost.

Database, no data dropped: synchronous=NORMAL, journal_size_limit 64 MB,
hourly PASSIVE checkpoint + PRAGMA optimize, idx_events_session_created
(replacing the redundant idx_events_session), watchdog reads
sessions.transcript_path, transcript parsed before the hook's write
transaction, GET /api/sessions/:id?events=0 for the web page (reloads only
on its own session, debounced), streamed export, transactional clear-data
and chunked cleanup, subagent import reads tool_use_ids once, runtime logs
rotated past 5 MB.

server/db.js

@@ -144,6 +144,13 @@ const db = new Database(DB_PATH);
 db.pragma("journal_mode = WAL");
 db.pragma("foreign_keys = ON");
 db.pragma("busy_timeout = 5000");
+// WAL + NORMAL never corrupts the file; a power cut can lose only the last
+// commits, which hooks re-send. FULL fsynced every commit — several per hook.
+db.pragma("synchronous = NORMAL");
+// A checkpoint truncates the WAL back to this. Unset, one big transaction
+// (an import, a cleanup) left a WAL of hundreds of MB that never shrank while
+// any dashboard kept the database open. See also `maintainDatabase`.
+db.pragma("journal_size_limit = 67108864");
 
 db.exec(`
   CREATE TABLE IF NOT EXISTS sessions (
@@ -298,7 +305,12 @@ db.exec(`
 
   CREATE INDEX IF NOT EXISTS idx_agents_session ON agents(session_id);
   CREATE INDEX IF NOT EXISTS idx_agents_status ON agents(status);
-  CREATE INDEX IF NOT EXISTS idx_events_session ON events(session_id);
+  -- (session_id, created_at): a session's newest event and its time order,
+  -- read by the watchdog every 15 s and by every lane payload. Without it each
+  -- read walked the rows' overflow chains (created_at sits after data).
+  CREATE INDEX IF NOT EXISTS idx_events_session_created ON events(session_id, created_at);
+  -- A prefix of idx_events_session_type: never needed, ~1% of the file.
+  DROP INDEX IF EXISTS idx_events_session;
   CREATE INDEX IF NOT EXISTS idx_events_type ON events(event_type);
   CREATE INDEX IF NOT EXISTS idx_events_created ON events(created_at DESC);
   CREATE INDEX IF NOT EXISTS idx_sessions_status ON sessions(status);
@@ -2127,4 +2139,34 @@ const stmts = {
   ),
 };
 
-module.exports = { db, stmts, DB_PATH, DEFAULT_PRICING, applyIntroPricing, topUpDefaultPricing };
+/**
+ * Periodic upkeep, run hourly by the server: a PASSIVE checkpoint (never waits
+ * on a reader — the other dashboard's), after which the next write truncates
+ * the WAL to `journal_size_limit`; and `PRAGMA optimize`, which refreshes the
+ * planner's statistics only where they went stale. Never VACUUM: it rewrites
+ * the whole file under an exclusive lock.
+ */
+function maintainDatabase() {
+  const out = {};
+  try {
+    out.checkpoint = db.pragma("wal_checkpoint(PASSIVE)", { simple: false });
+  } catch (err) {
+    out.checkpointError = err.message;
+  }
+  try {
+    db.pragma("optimize");
+  } catch (err) {
+    out.optimizeError = err.message;
+  }
+  return out;
+}
+
+module.exports = {
+  db,
+  stmts,
+  DB_PATH,
+  DEFAULT_PRICING,
+  applyIntroPricing,
+  topUpDefaultPricing,
+  maintainDatabase,
+};