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/pages/ActivityFeed.tsx

@@ -1,6 +1,7 @@
 /**
  * @file ActivityFeed.tsx
  * @description Real-time feed of agent events with server-driven filters and
+ * a right-click session menu per row (`SessionRowMenu`),
  * batched pagination. Clicking a row toggles the inline EventDetail payload
  * view; the "View session" Link navigates to the session page. Live events
  * trigger a debounced, filter-aware refetch that preserves the user's
@@ -71,6 +72,8 @@ import { useDataScope } from "../lib/dataScope";
 import { AgentStatusBadge } from "../components/StatusBadge";
 import { EmptyState } from "../components/EmptyState";
 import { EventDetail } from "../components/EventDetail";
+import { useContextMenu } from "../components/ContextMenu";
+import { SessionRowMenu } from "../components/SessionRowMenu";
 import {
   EventFilters,
   EMPTY_FILTERS,
@@ -101,6 +104,7 @@ const MAX_REFRESH = 500;
 const REFRESH_DEBOUNCE_MS = 500;
 
 export function ActivityFeed() {
+  const eventCtx = useContextMenu<string>();
   const { t } = useTranslation("activity");
   const [events, setEvents] = useState<DashboardEvent[]>([]);
   const [total, setTotal] = useState(0);
@@ -318,6 +322,14 @@ export function ActivityFeed() {
 
   return (
     <div className="animate-fade-in">
+      {eventCtx.menu && (
+        <SessionRowMenu
+          session={{ id: eventCtx.menu.item }}
+          x={eventCtx.menu.x}
+          y={eventCtx.menu.y}
+          onClose={eventCtx.close}
+        />
+      )}
       <div className="flex flex-wrap items-center justify-between gap-3 mb-6">
         <div className="flex items-center gap-3">
           <div className="w-9 h-9 rounded-xl bg-accent/15 flex items-center justify-center">
@@ -423,6 +435,7 @@ export function ActivityFeed() {
                         }
                       }}
                       aria-expanded={isOpen}
+                      onContextMenu={(e) => eventCtx.open(e, event.session_id)}
                       className="flex items-center px-5 py-3.5 gap-4 hover:bg-surface-4 transition-colors cursor-pointer select-none"
                     >
                       <ChevronRight