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.

client/src/components/WorkspaceTree.tsx

@@ -37,7 +37,8 @@ import { AddLaneModal } from "./lanes/AddLaneModal";
 import { DestructiveLaneModal } from "./lanes/DestructiveLaneModal";
 
 /** The workspace (and attached run) the Workspace page shows, from its URL. */
-function selectedFrom(pathname: string, search: string) {
+/** The workspace, pane run and replayed session the URL names (Workspace page only). */
+export function selectedFrom(pathname: string, search: string) {
   if (!pathname.startsWith("/workspace")) return { lane: null, run: null, session: null };
   const p = new URLSearchParams(search);
   const v = p.get("lane");