[grade=B urn:ump:35dpnggtxsqrxvlqm2d2buqkbnggw3acflbccnkqpqyiiijcxx3q] fix(DC-170): MCP truth batch — 6 dead tools fixed, full-catalog drift gate

Audit P0-5 + deploy_app truth (batch 5 of the 2026-10-27 sweep, AUDIT-2026-10-27.md committed here):

ROUTE ADDITIONS:
- routes/containers.js GET / — container list (dockerode listContainers);
  the router had NO list route, so dashcaddy_list_containers 404'd always
- routes/dns.js GET /records — record list via active provider with a
  list-records capability guard (501 + guidance for push-only providers
  like RFC2136); dashcaddy_list_dns called GET /dns, never existed

HANDLER FIXES (src/mcp/mcp-core.js):
- get_service resolves from GET /services by id/name (single-service GET
  never existed) with a known-ids 404
- check_health + diagnose -> /health/service/:id and /health/services
  (both previously hit nonexistent routes)
- container_action remove -> DELETE /containers/:id (was /:id/remove)
- system_health/system_metrics via apiCall error envelope (metrics text
  capped at 64KB)
- search_catalog applies category filter client-side (/catalog/search
  has no category param — constraint was silently dropped)
- generate_caddyfile defaults authService=status when auth:true (auth
  flag alone silently produced UNGATED Caddyfiles)
- deploy_app honest re-contract: registers service + generates
  Caddyfile, does NOT claim image pull/container creation/deployed:true;
  base domain read from /config (hardcoded owner .sami TLD removed);
  caddy-code failure now surfaces as caddyfileError + FAILED message
- list_fleet description gains Premium hint

VERIFIER (audit #40): EXPECTED table 12 -> 34 rows covering EVERY tool's
(method,path); NEW Layer-3 handler-derived test drives the real
createToolHandler for all 28 tools and strictly resolves every captured
call mount-aware (a vacuous first draft of this gate was caught and
fixed pre-grade); extractRoutes regex extended to apiRouter.get inline
decls; Bearer credential-passthrough test added (DC-162 coverage gap)
NEW TESTS: dns-records.routes.test.js (5 route-level cases incl. 501
capability behavior); deploy_app partial-failure + no-.sami tests

HOST RELIABILITY (same sweep, evidenced here): jest maxWorkers 50% —
default 5-worker runs repeatedly OOM-killed this host's gateway
(dmesg 2026-10-29 00:58:40; swap was 4G/4G full). Gateway protected
separately via systemd OOMScoreAdjust=-500 drop-in + /swapfile2 (host
ops, graded B urn:ump:35dpnggtxsqrxvlqm2d2buqkbnggw3acflbccnkqpqyiiijcxx3q).
DC-171 DNS provider-parity ticket (Sami, plug-in-directly) appended to
backlog.

Full suite: 173/173 suites, 3740/3740 tests. Judge B r1
(urn:ump:jsobkg2t2omzvpinel2fufk7sspoy3vubsrth3e6lat3ygolvffq) blockers
all fixed: dns.js 501 arg order (the file aliases error() message-first
— the sweep's 'reversed-arg' finding was a false positive for its 7
sites; lesson #14), deploy_app partial-failure honesty, handler-derived
verifier.

dashcaddy-api/routes/dns.js

@@ -65,6 +65,21 @@ module.exports = function({
     }
   }, 'dns-provider-status'));
 
+  // GET /records — list DNS records via the active provider (DC-170, audit
+  // P0-5: the MCP dashcaddy_list_dns tool called GET /dns, which never existed)
+  // NOTE: this file's errorResponse is responses.js `error(res, message, code)`
+  // (message FIRST) — the reversed-arg audit finding does not apply here.
+  router.get('/records', asyncHandler(async (req, res) => {
+    const zone = req.query.zone || (siteConfig.tld ? String(siteConfig.tld).replace(/^\./, '') : '');
+    const provider = dns.getActiveProvider ? dns.getActiveProvider() : null;
+    if (!provider || (provider.supportsCapability && !provider.supportsCapability('list-records'))) {
+      return errorResponse(res, 'Record listing not supported by current DNS provider', 501);
+    }
+    const result = await provider.listRecords({ zone });
+    const records = Array.isArray(result) ? result : (result && result.records) || [];
+    success(res, { zone, count: records.length, records });
+  }, 'dns-records-list'));
+
   // ===== UNIVERSAL RECORD ENDPOINTS (work with any provider) =====
 
   // POST /universal/record — Create a DNS record via any provider