Add HTTP route method matching

[kacy]

Summary

• add match_methods as a first-class HTTP route matcher in manifests, persisted route state, and runtime snapshots
• make the router prefer narrower method-constrained routes after path and header specificity
• expose method-constrained routes in service and status JSON, and document the new ingress policy surface

Validation

• YOQ_SKIP_SLOW_TESTS=1 zig build test
• Result: 1759 passed; 26 skipped; 0 failed