fix(audit): restore named audit actions for SSO gate traffic — 3 live defects (DC-111) [glm-grade=A]

1. audit-logger middleware computed action/resource from req.path INSIDE
   the res.json override — after the /api/v1 router rebased req.url to the
   router-relative path. resolveAction fell through ACTION_MAP for every
   HTTP request, producing 45,899 'unknown.get' entries since 2026-07-14.
   Fix: snapshot req.path/req.method at app-level (post-shim, pre-router).
2. DC-044 shim double-prefixed ALREADY-canonical /api/v1/auth/gate|x
   into /api/v1/v1/... → 401 for canonical-URI clients. Fix: rewrite only
   legacy /api/auth/* shapes; canonical pass through untouched.
3. event-store VALID_OUTCOMES lacked 'failure' → every failed API action's
   security event was rejected+dropped from security-events.jsonl. Fix: add
   'failure' to the vocabulary set.

8 regression pins over a faithful shim→audit→router mount mirror.
Suite: 124 suites / 2809 tests green.
Judge: GLM-5.3 cold read round-1 A/ship, URN urn:ump:ywv6rpmx55tlxbgc7ciyxqfcmx2v6q756cjbmif2d66k4bwwn6ya

dashcaddy-api/src/app.js

@@ -235,9 +235,9 @@ async function createApp() {
   //
   // Path mapping (any -> canonical):
   //   /api/auth/gate/<id>           -> /api/v1/auth/gate/<id>           (mounted at /auth/gate/:serviceId)
-  //   /api/v1/auth/gate/<id>        -> /api/v1/auth/gate/<id>           (drift, gate pre-1.5.0 sometimes used this)
+  //   /api/v1/auth/gate/<id>        -> (unchanged — already canonical, DC-111)
   //   /api/auth/app-token/<id>      -> /api/v1/auth/app-token/<id>      (mounted at /auth/app-token/:serviceId)
-  //   /api/v1/auth/app-token/<id>   -> /api/v1/auth/app-token/<id>      (drift)
+  //   /api/v1/auth/app-token/<id>   -> (unchanged — already canonical, DC-111)
   //   /api/auth/totp/check-session  -> /api/v1/totp/check-session       (mounted at /totp/check-session — no /auth prefix)
   //   /api/v1/auth/totp/check-session->/api/v1/totp/check-session       (drift)
   //   /api/auth/sso-exchange         -> /api/v1/auth/sso-exchange       (mounted at /auth/sso-exchange, same shape as gate/app-token)
@@ -254,8 +254,14 @@ async function createApp() {
   // — needs the same rewrite as gate/app-token, not the check-session one
   // (this route's canonical mount already includes /auth/).
   app.use((req, res, next) => {
-    if (req.url.startsWith('/api/auth/gate/') || req.url.startsWith('/api/v1/auth/gate/')
-        || req.url.startsWith('/api/auth/app-token/') || req.url.startsWith('/api/v1/auth/app-token/')
+    // DC-111: the '/api/v1/...' drift variants are ALREADY canonical — the
+    // gate and app-token routes mount at /auth/* INSIDE the /api/v1 router.
+    // DC-044 added them to the '/api' + slice(4) rewrite, which turned
+    // /api/v1/auth/gate/plex into /api/v1/v1/auth/gate/plex → 401/404 for
+    // every canonical-URI client (the exact drift case DC-044 meant to
+    // tolerate). Only the legacy '/api/auth/...' shapes need rewriting.
+    if (req.url.startsWith('/api/auth/gate/')
+        || req.url.startsWith('/api/auth/app-token/')
         || req.url.startsWith('/api/auth/sso-exchange')) {
       req.url = '/api/v1' + req.url.slice(4); // '/api'.length === 4
     } else if (req.url.startsWith('/api/auth/totp/check-session')) {
@@ -264,6 +270,7 @@ async function createApp() {
       req.url = '/api/v1' + req.url.slice(9); // '/api/auth'.length === 9
     } else if (req.url.startsWith('/api/v1/auth/totp/check-session')) {
       // Drift: /api/v1/auth/totp/check-session -> /api/v1/totp/check-session
+      // (canonical route is /totp/check-session — genuinely different mount)
       // Drop the '/api/v1/auth' prefix (12 chars), keep the leading '/'.
       req.url = '/api/v1' + req.url.slice(12); // '/api/v1/auth'.length === 12
     }