[lesnik512]

When instrument startup or application preparation raises, including KeyboardInterrupt or SystemExit, roll back only successfully started instruments in reverse order. Preserve the original failure with ordinary cleanup errors attached as notes, leave the bootstrapper unbootstrapped, and reject reuse after failure. Document the terminal failure contract.

Fix FastMCP lean Sentry transaction naming by assigning names in one place: preserve existing names, otherwise resolve full matched route templates through Mount and Host containers. Stop at the first full match, including opaque routes, and use scope route metadata only when no route tree was supplied. This covers newer Starlette versions that populate scope["route"] themselves.

Also specialize the Swagger instrument config in its typing test.

Closes #382.

Validation

• Refreshed dependencies with just install, matching CI's upgrade recipe.
• just test-ci: 604 passed, 100% coverage.
• just lint-ci: passed, including repository-wide ty.
• Failing regressions verified before fixes for interrupted startup, mounted FastAPI routes, Host routing, and opaque route selection.
• Standards and spec reviews: no findings; both reviewers independently ran 86 focused tests.