fix(adapters): to_openapi runtime-truthful projection (PRJ-01..05, PRJ-11..15)

- /search, /schema: document the envelope wrapper and the real item/spec
  fields (PRJ-01/02); /search drops unreachable 401/403, documents 404
  (PRJ-15)
- error statuses: 422 for dispatch-path INVALID_INPUT /
  INVALID_OPERATION_TYPE; extractor 400s documented as the plain-text
  gap they are (PRJ-03); operation-declared errors projected by
  http_status with x-runtime-behavior: 500 on non-HTTP_* codes (PRJ-04
  project-honest decision) — no runtime changes
- /subscribe: 200+SSE only; event:error terminal contract documented
  (PRJ-05, GW-12)
-  components for requests/responses; CallRequest no longer inlined
  per-path (PRJ-14); all library expect() paths removed (PRJ-11)
- error projections folded into BTreeMaps: same registry =>
  byte-identical doc, sorted enums (PRJ-12)
- components.securitySchemes.bearerAuth + top-level security (PRJ-15)
- info.version 1.1.0 -> 1.2.0 (ADR-045 minor: additive documentation of
  the settled runtime contract)
- 31 unit tests incl. golden print-level assertions mirroring the routes
  tests' actual bodies and a determinism test

Verification: cargo test (288), clippy --all-targets -D warnings, fmt
--check, cargo doc --no-deps, cargo test --all-features (all green in a
clean worktree at HEAD; shared tree carries parallel agents' edits).

tests/full_surface.rs

@@ -265,7 +265,7 @@ async fn full_surface_gateway_over_http() {
         .unwrap();
     assert_eq!(resp.status(), 200);
     let body: serde_json::Value = resp.json().await.unwrap();
-    assert_eq!(body["info"]["version"], "1.1.0");
+    assert_eq!(body["info"]["version"], "1.2.0");
     assert!(body["paths"].get("/publish").is_some());
     assert!(body["paths"].get("/call").is_some());
 }