- apply bearer_auth_middleware route_layer AFTER the extra_routes merge,
so assembly-layer custom routes resolve the bearer token by default
(ADR-046 §4); per-route opt-out via the route's own layer remains
- enforce RESERVED_PATHS per-method at build time: a probe MethodRouter
occupied on all methods is pre-merged against extras, so a custom
POST /search panics like a same-method overlap (ADR-046 §3)
- tests: auth resolves through an extra route; an extra route with its
own layer opts out; reserved-path merge panics; non-reserved
different-method merge stays legal; MCP bearer-gate test stays green
- ADR-046 §3: one sentence restating the per-method rejection rule
Verification: cargo test (215) ok, cargo test --all-features (260 +
integration) ok, clippy -D warnings (default + all-features) ok,
cargo fmt --check ok.