Simplify dashboard nav, add i18n selector, and fix Brief crash

[minsing-jin]

Summary

• Group the crowded dashboard nav into primary Setup/Feed/Brief/Chat links plus Read, Steer, Tools, SaaS, and More disclosure surfaces without removing existing routes.
• Add a left-side language selector for Korean, Chinese, and English with localStorage persistence and i18n hooks for shell, setup, feed, and brief entry points.
• Fix local SQLite schema migration ordering so older DBs missing evolved columns are migrated before indexes are created, preventing /brief from crashing.
• Add issue ux: simplify dashboard navigation, add language selector, and fix Brief SQLite crash #34 route grouping documentation and regression coverage for navigation reachability, language persistence, SQLite migration, and /brief rendering.

Verification

• git diff --check: passed.
• python3 -m pytest -p no:rerunfailures tests/test_issue34_nav_i18n_brief.py tests/test_v3_brief.py tests/test_local_sqlite_setup_schema.py tests/test_issue32_route_inventory.py: 79 passed.
• python3 -m pytest -p no:rerunfailures: 924 passed, 1 warning.
• Local preview previously verified: http://127.0.0.1:8767/brief and /setup returned HTTP 200.

Ouroboros

• Official run: job_857b8f2b5e44, session orch_f9a2eb42432c, execution exec_0161a01ad8ea.
• Run completion evidence: execution.terminal and orchestrator.session.completed events at 2026-05-19 13:39:11, with 11/11 AC and 77/77 Sub-AC complete.
• Known limitation: the background JobManager wrapper stayed running, and ouroboros_job_result reported Job still running: running despite the terminal execution events.
• Formal ouroboros_evaluate was attempted twice and timed out after 120 seconds with no evaluation events recorded.
• Bounded fallback ouroboros_qa against code-level evidence passed: 0.92 / 1.00, threshold 0.90.
• Evolve/Ralph recovery was attempted with low-resource settings. job_418b74fd2095 and job_be0afb63df62 stalled at generation 0 and were cancelled as stale. job_845646d7a7d4 failed on the cancelled lineage. Direct ouroboros_evolve_step timed out. ouroboros_ralph failed before job creation because the Ouroboros MCP event store hit SQLAlchemy QueuePool exhaustion.
• No unrelated processes were killed. Memory pressure stayed safe, so the blocker is the Ouroboros MCP event-store connection pool rather than repository tests or system OOM.
• Isolated rerun on 2026-05-21 KST used HOME=/private/tmp/hedwig-issue34-ouroboros-home so global Ouroboros state was not modified. Isolated ouroboros run workflow completed as session orch_e93e6c577281 with all 6 issue ux: simplify dashboard navigation, add language selector, and fix Brief SQLite crash #34 validation ACs complete and no code changes needed.
• Isolated rerun verification: focused tests 79 passed in 10.14s, full tests 924 passed, 1 warning in 81.97s, and git diff --check passed.
• Retried MCP ouroboros_evaluate still timed out after 120 seconds with no evaluation events. Retried MCP ouroboros_ralph created job_c4121a3163fc, but it remained at generation 0 and was cancelled as stale. Isolated auto --complete-product attempts blocked before Seed/Ralph handoff because of unresolved ambiguity or the fixed 120-second interview phase timeout.

Closes #34