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.

docs/API.md

@@ -1324,7 +1324,7 @@ Returns `{ session }`.
 GET /api/sessions/:id
 ```
 
-Returns single session details.
+Returns single session details: `{session, agents, events, workflows}`. `events` is every event of the session with its full payload — on a long session hundreds of MB — so `?events=0` answers it as `[]`; the web page uses that and reads its timeline through the paginated events call (the CLI's `agenthub session <id>` still takes them all).
 
 **Path Parameters:**
 
@@ -1867,10 +1867,10 @@ curl -X DELETE http://localhost:4820/api/pricing/gpt-5.1-codex
 #### Total Cost
 
 ```http
-GET /api/pricing/cost?tz_offset=<minutes>&sources=<csv>
+GET /api/pricing/cost?tz_offset=<minutes>&sources=<csv>&lane=<id>
 ```
 
-The total cost with a per-model `breakdown`, plus `daily_costs: [{date, cost}]` by local date (`tz_offset` is the browser's `getTimezoneOffset()`; the status bar's **Today** is the entry for today). A day is the day the tokens were SPENT: each session's total is split over the local days of its `token_usage_hourly` rows (one per UTC hour, from each Claude transcript message's timestamp), and whatever the total holds beyond those rows — a session recorded before that table and whose transcript is gone, sub-agent files, Codex and Antigravity sessions — is booked to the session's start date. The days always add up to the total.
+The total cost with a per-model `breakdown`, plus `daily_costs: [{date, cost}]` by local date (`tz_offset` is the browser's `getTimezoneOffset()`; the status bar's **Today** is the entry for today). A day is the day the tokens were SPENT: each session's total is split over the local days of its `token_usage_hourly` rows (one per UTC hour, from each Claude transcript message's timestamp), and whatever the total holds beyond those rows — a session recorded before that table and whose transcript is gone, sub-agent files, Codex and Antigravity sessions — is booked to the session's start date. The days always add up to the total. `lane=<id>` narrows it to the sessions that workspace owns (`sessions.lane_id`, or held by one of its `dashboard_runs` and not stamped yet — the rule of `GET /api/sessions?lane=`; a non-numeric id is `400 INVALID_INPUT`); the status bar shows it as **Workspace $…** on the Workspace page, beside **Session $…** from `GET /api/pricing/cost/:sessionId` for the replayed session or the focused pane's.
 
 ```bash
 curl "http://localhost:4820/api/pricing/cost?tz_offset=-420"