fix: restore OpenCode sessions after browser refresh

[danshapiro]

Summary

• replay canonical terminal sessionRef on terminal.created and terminal.attach.ready
• centralize client reconciliation of { terminalId, sessionRef } from inventory, create, attach-ready, and association messages
• preserve OpenCode/Codex restore behavior by clearing stale legacy identity and stale Codex durability when provider identity changes
• add regression coverage for OpenCode refresh recovery before stale terminal cleanup

Verification

• npm run typecheck
• npm run test:vitest -- test/unit/client/components/App.ws-bootstrap.test.tsx test/unit/client/components/TerminalView.resumeSession.test.tsx test/unit/client/components/TerminalView.lifecycle.test.tsx test/e2e/terminal-restart-recovery.test.tsx test/e2e/codex-refresh-rehydrate-flow.test.tsx --run -t "OpenCode sessionRef|terminal.session.associated|terminal.created live-only|terminal.created when the server replays it|persists canonical durable sessionRef|inventory recovers a missing sessionRef|registers regenerated restart request ids|restores the same Codex session after a refresh|sessionRef replayed by terminal.attach.ready|replays OpenCode sessionRef|buildTerminalSessionRef"
• npm run test:vitest -- --config vitest.server.config.ts test/server/ws-protocol.test.ts test/unit/server/terminal-registry.test.ts --run -t "OpenCode sessionRef|buildTerminalSessionRef"

Known Verification Note

• Coordinated npm test previously passed the client suite and then failed only on the pre-existing OpenCode real-provider DB-row timeout in test/integration/real/coding-cli-session-contract.test.ts; the user accepted that as a flake for this landing.
• Final fresheyes review was waived by the user after the fresheyes process exceeded its expected polling window and was stopped per instruction.