feat: persist permission auto-accept on server (#2158)

Move per-session permission auto-accept policy ownership from the UI to the
OpenChamber server so enabled sessions continue running when clients disconnect
or the server restarts.

- persist explicit per-session policies in OpenChamber settings
- inherit the nearest explicit policy across subagent session hierarchies
- allow child sessions to opt out of an inherited parent policy
- immediately accept matching global and directory-scoped pending requests
- process future requests without requiring a connected UI client
- reconcile pending permissions after startup and event-stream reconnects
- deduplicate concurrent requests and retry transient reply failures
- synchronize policy updates across connected clients
- migrate existing browser-persisted policies to server storage
- suppress auto-accepted permission cards before they enter UI state
- show deduplicated permission toasts for inactive sessions
- preserve foreground-only permission handling in VS Code
- integrate directory-aware notification routing from main
- add coverage for persistence, inheritance, retries, reconciliation, pending
  requests, client hydration, and inactive-session toasts

packages/web/server/lib/permission-auto-accept/DOCUMENTATION.md

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+# Permission Auto-Accept
+
+## Purpose
+
+This module owns the authoritative permission auto-accept policy for web, desktop, and mobile runtimes. Policy is persisted in OpenChamber settings so permission handling survives UI disconnects and server restarts.
+
+## Policy
+
+`permissionAutoAccept.sessions` contains explicit per-session boolean policies.
+
+Policy inheritance uses the nearest explicit session value. A child `false` therefore overrides a parent `true`; descendants without an explicit value inherit from their nearest configured ancestor.
+
+## Runtime
+
+`createPermissionAutoAcceptRuntime` loads and serializes policy writes, subscribes to the global OpenCode event hub, caches session lineage, retries transient replies, and reconciles pending permissions after startup, reconnect, and policy enablement. Enabling Auto-Accept for a session immediately accepts matching pending requests and keeps handling future requests without requiring a connected UI.
+
+Unknown lineage and failed policy loads fail closed. A failed pending-permission fetch is distinct from an empty successful response and never clears policy state.
+
+## Routes
+
+- `GET /api/permission-auto-accept`
+- `PUT /api/permission-auto-accept/sessions/:sessionId`
+
+These are normal authenticated OpenChamber runtime routes. They must not be added to browser URL-token allowlists.
+
+## UI ownership
+
+`packages/ui/src/stores/permissionStore.ts` is a projection of server policy and does not persist an independent policy. The server is the sole responder and the UI renders pending requests until the authoritative `permission.replied` event arrives.
+
+VS Code retains its foreground-only implementation because it does not run the web server runtime.
+
+## Tests
+
+`runtime.test.js` covers restart persistence, nearest explicit subagent inheritance, missing-lineage lookup, retry/deduplication, and reconnect reconciliation.