fix: inherit provider thinking and use rapid orchestration ci

[numnx]

What changed

• Added an explicit inherit option for route-level provider thinking overrides so stale route thinkingMode values can be cleared without deleting unrelated route provider overrides.
• Fixed project/sprint Base Provider Configuration resolution so sparse provider-instance overrides merge field-by-field with the inherited named instance instead of resetting omitted fields such as enabled, weight, and maxConcurrentTasks.
• Clamped shared dropdown positioning so project-scope Base Provider Configuration selects stay clickable inside the viewport before saving.
• Updated the mockup sprint pentest workflow to run the rapid orchestration lane instead of the full orchestration pentest lane, including the workflow-health regression test.
• Updated user and developer docs for provider thinking inheritance, base provider inheritance, and rapid orchestration CI behavior.

Why

Provider-level thinking budget changes could be shadowed by an older route-level thinking override, making the saved base provider setting appear ineffective at runtime. Sparse project base-provider overrides could also replace an inherited provider instance with only the edited fields, causing omitted eligibility fields to fall back to provider defaults instead of the parent scope. CI was also spending too long in the full orchestration pentest path, so the workflow now uses the rapid lane while leaving the full script available for manual escalation.

Validation

Passed locally:

pnpm vitest run tests/backend/ci/workflow-health.test.ts tests/backend/services/settings-resolution-service.test.ts tests/dashboard/settings-page.test.tsx tests/dashboard/v2/avantgarde-select.test.tsx
pnpm run lint
pnpm run build

Manual dashboard validation:

• Restarted the dev server on http://localhost:4444.
• Verified project-scope Base Provider Configuration can open the named local CLI provider card, show the enabled switch, save the enabled state, and retain it after reload across approved test project scopes.

Risk and rollback

• Runtime risk is limited to settings resolution for sparse base provider overrides, route provider override editing, dropdown positioning, and the orchestration validation workflow.
• If deeper CI coverage is needed again by default, revert the workflow step to the full orchestration pentest command. The full script remains available manually.