* test(collab): add deterministic browser sessions
- Extract a typed room transport boundary around Trystero
- Add a development-only WebSocket relay transport for browser tests
- Cover two-peer edits, awareness, departure cleanup, and reconnect convergence without public network services
* fix(collab): harden browser test transport
- Scope collaboration controls to explicit development test hooks
- Validate bounded relay messages and reject duplicate action receivers
- Remove only awareness clients owned by a departing peer
- Guarantee relay and browser cleanup after setup failures
* fix(collab): strengthen browser session coverage
- Prevent remote awareness rebroadcast and track ownership by transport peer
- Guard and validate the development relay lifecycle
- Simulate a network partition with retained peers and concurrent offline edits
- Make browser and relay setup and teardown failure-safe
* test(collab): prove partitioned peer convergence
- Queue and assert traffic during a deterministic network partition
- Converge non-conflicting edits from retained host and guest sessions
- Reject relay startup failures and guard test-only browser APIs
- Rename first-party API, RPC, JSON, CORS, SVG, JSX, and related identifiers to preserve acronym casing
- Keep upstream and serialized boundary names unchanged
- Add a lint guardrail and migration notes for exported APIs
- Expose window.openPencil.getStore() instead of a direct store property
- Update E2E helpers and specs to use the bridge getter
- Add lint coverage preventing direct window.openPencil.store access
- Move test-only write-count, mock-handle, and saved-open globals under window.openPencil.test
- Keep external Tauri and Vite injected globals separate from app-owned browser bridge hooks
- Validate check plus autosave and chat E2E coverage
- Rename window-api to browser-bridge to describe the app-to-browser test hook boundary
- Rename the chat transport hook to exposeChatTransportOverride and window.openPencil.setChatTransport
