feat(session): record location switches - #41899

Summary

• project durable session moves into a location-switched timeline message with current and previous location details
• send directory changes to subsequent model context and preserve them through compaction
• render location switches in the V2 TUI and remove the duplicate synthetic move reminder
• regenerate the public client message union

Testing

• bun typecheck in packages/schema, packages/core, packages/client, and packages/tui
• repository-wide typecheck from the pre-push hook (33 packages)
• focused Core move, projector, message-lowering, and shared-schema tests (32 passed)
• full TUI data-context test file (41 passed)
• full Schema test suite: 42 passed; one unrelated existing Agent.Color contract test failed