fix: honor route thinking settings

[numnx]

What changed

• Propagate each Route Mapping thinking override through structured planning requests and their reflection/retry calls.
• Add model-aware Codex reasoning options so Sol-family models support max and ultra, while other Codex models remain capped at xhigh.
• Preserve the active Settings category, focused card, and invocation route across a same-tab hard refresh.
• Update canonical and public Route Mapping documentation and add backend/dashboard regression coverage.

Why

Route Mapping correctly persisted the selected model and thinking value, but the virtual planning path forwarded the resolved model without forwarding the resolved thinking mode. Planning therefore ran with the provider default despite the saved override. The settings UI also lacked Sol-specific reasoning levels and did not retain its focused navigation context after a hard refresh.

User impact

Planning overrides such as Codex xhigh now reach both the initial planning call and structured retries. Sol-family Codex routes expose max and ultra, and a refreshed Settings page returns to the same category, Route Mapping card, and invocation route in the current tab.

Validation

• pnpm run ci — passed
  • quality guardrails
  • dependency audit (no known vulnerabilities)
  • strict TypeScript lint/typecheck
  • backend coverage: 438 files, 5,510 tests passed, 7 skipped
  • dashboard: 241 files, 2,154 tests passed, 2 skipped
  • production server and dashboard build
• Focused backend and dashboard regression suites — 265 tests passed, 2 skipped
• Rebuilt local dashboard — /health reported all components UP; Settings route loaded successfully

Risk and rollback

Risk is limited to model-aware thinking validation/normalization and same-tab Settings navigation state. Unsupported reasoning values continue to normalize to the provider default. Roll back by reverting commit f9f54ea3d.