1.1.0: stable release on the alpha7 contract

Bundles three operator-experience features from the 1.0.0 production
soak (outlier filtering, per-metric/adaptive sampling, deploy-event
annotations), the four 1.0.1 correctness fixes (request_id strict
validation, top-level try/catch, cwv-rid skip on shared-cacheable
responses, PERFORMANCE.md sampling clarification), and approximately
twenty code-review polish items from a full review pass on 1.0.0.

No contract changes. The alpha7 collector contract that was frozen
at beta1 remains stable.

Operators upgrading directly from 1.0.0 get all of the above in
one step.

See ROADMAP.md, SECURITY.md, PERFORMANCE.md, docs/collector-contract.md
for the full picture.