Fix workspace roadmap route redirect

[jaeyunha]

Closes #382

Summary

• salvage from completed visible lane: add workspace roadmap aliases and middleware route handling
• preserve initiatives compatibility and add middleware/page regression coverage

Verification / blocker

• make check ✅
• npx vitest run tests/middleware.test.ts tests/initiatives-page.test.tsx ✅ (48 tests)
• focused Playwright on isolated port 3025 ❌ blocked in auth setup: /api/test/create-session 503 DB bootstrap
• make test-e2e ❌ baseline failed before changes due auth setup /api/test/create-session 404 from port mismatch

QA_BLOCKED: preserved after prior push auth failure; needs fresh browser/controller acceptance before merge.

[jaeyunha]

Superseded by #441 — consolidating duplicate attempts at the same underlying issue. Closing as part of PR-queue triage.