fix(hub): reopen legacy proposals on exact fast path

[blancmathis]

Summary\n\n- keep restored proposal rooms in while the Hub snapshot is stale\n- reuse exact legacy proposal authorities without a proposal-state ref only from a fresh, openable snapshot\n- return opening on both exact and cached warm paths\n- bump the package to \n\n## Validation\n\n- exact-commit

context-room@0.6.13 test
node --check src/context_room.mjs && node --check bin/context-room.mjs && node --check bin/context-room-remote.mjs && node --check scripts/update-context-rooms.mjs && node --check scripts/run-tests.mjs && node --check scripts/audit-layout-css.mjs && node scripts/audit-layout-css.mjs && node scripts/run-tests.mjs

Layout CSS audit passed.
ok - test/agent_cli.test.mjs (3.7s)
ok - test/ci_workflow.test.mjs (0.1s)
ok - test/acceptance_timeout.test.mjs (15.6s)
ok - test/bin_context_room_shared_cli.test.mjs (27.2s)
ok - test/cli_event_schema.test.mjs (0.1s)
ok - test/cli_registry.test.mjs (0.1s)
ok - test/codex_composer_bridge.test.mjs (0.1s)
ok - test/cli_args.test.mjs (26.0s)
ok - test/codex_prompt_center.test.mjs (6.2s)
ok - test/context_diagnostics.test.mjs (0.1s)
ok - test/context_engine.test.mjs (0.1s)
ok - test/context_cli_adapters.test.mjs (26.0s)
ok - test/context_inventory.test.mjs (0.3s)
ok - test/cli_contract_regressions.test.mjs (129.6s)
ok - test/context_settings.test.mjs (0.1s)
ok - test/context_snapshots.test.mjs (0.1s)
ok - test/context_room.test.mjs (104.2s)
ok - test/doc_metadata.test.mjs (0.2s)
ok - test/docqa_concurrency.test.mjs (5.3s)
ok - test/document_extensions.test.mjs (0.1s)
ok - test/document_metadata_engine.test.mjs (0.2s)
ok - test/event_journal_context_engine.test.mjs (0.1s)
ok - test/filesystem_lock.test.mjs (0.9s)
ok - test/github_app_token.test.mjs (0.3s)
ok - test/doc_agent.test.mjs (23.5s)
ok - test/context_hub.test.mjs (212.7s)
ok - test/hub_shared_capability_p1.test.mjs (7.7s)
ok - test/markup_accessibility.test.mjs (0.3s)
ok - test/package_privacy.test.mjs (0.1s)
ok - test/product_compression.test.mjs (0.1s)
ok - test/qm_gateway.test.mjs (1.6s)
ok - test/read_only_context_surfaces.test.mjs (1.4s)
ok - test/hosted_scope_boundary.test.mjs (99.7s)
ok - test/hosted_private_publish.test.mjs (114.8s)
ok - test/remote_http_transport.test.mjs (1.4s)
ok - test/remote_identity.test.mjs (0.1s)
ok - test/remote_image.test.mjs (0.1s)
ok - test/remote_image_workflow.test.mjs (0.2s)
ok - test/remote_profile_assets.test.mjs (1.1s)
ok - test/remote_server.test.mjs (3.5s)
ok - test/remote_ui_cli.test.mjs (0.8s)
ok - test/remote_accept_challenge.test.mjs (66.6s)
ok - test/review_authority.test.mjs (4.6s)
ok - test/remote_entrypoint_security.test.mjs (62.8s)
ok - test/server_security.test.mjs (3.7s)
ok - test/shared_cache_integrity.test.mjs (4.1s)
ok - test/shared_context_p1_regressions.test.mjs (23.2s)
ok - test/revision_integrity.test.mjs (48.3s)
ok - test/shared_project_creation.test.mjs (20.4s)
ok - test/shared_recovery_migration_p1.test.mjs (5.7s)
ok - test/shared_repository_identity.test.mjs (2.1s)
ok - test/startup_capability_p1.test.mjs (0.6s)
ok - test/update_context_rooms.test.mjs (0.1s)
ok - test/remote_ui_control.test.mjs (100.3s)
ok - test/shared_terminal_cas.test.mjs (26.3s)
ok - test/shared_context.test.mjs [3/4] (210.2s)
ok - test/shared_context.test.mjs [2/4] (235.3s)
ok - test/shared_context.test.mjs [1/4] (241.9s)
ok - test/shared_context.test.mjs [4/4] (223.3s)
ok - test/shared_context.test.mjs [performance] (10.4s)

60/60 test processes passed.: 60/60 processes passed\n- targeted backend fast path: 148 ms, no rematerialization\n- terminal/conflict/transient-catalogue regressions passed\n- proposal opening smoke: 12/12 across Chromium desktop/mobile, Firefox, and WebKit\n-

context-room@0.6.13 test:perf
playwright test --project=chromium-desktop --grep @Perf

Running 1 test using 1 worker

[1/1] [chromium-desktop] › test/e2e/performance.spec.mjs:41:1 › @Perf the unchanged workbench meets its hot runtime budgets
1 passed (15.2s): passed\n- layout recovery race: 5/5 after preserving the existing Hub refresh contract\n- , package privacy, found 0 vulnerabilities, and

context-room@0.6.13 prepack
npm run package:privacy

context-room@0.6.13 package:privacy
node scripts/check-package-privacy.mjs

Package privacy check OK (77 files).
context-room-0.6.13.tgz: passed\n\n## Risk\n\nThe legacy exception is fail-closed: it requires exact main/proposal heads, a fresh Hub snapshot, an openable review status, a completed conflict check, and no terminal or authority violation evidence. Protected state refs remain authoritative when present.