feat(forte-drop): wildcard IngressRoute for per-slug drop subdomains

No forte-helm chart change needed after all. The forteapp chart emits one exact
Host(`drop.forteapps.net`) route (apex: admin + /api + public /shared). Add an
ADDITIVE standalone IngressRoute for the per-slug wildcard *.drop.forteapps.net,
pointing at the SAME chart service (forte-drop-app:3000 — whose targetPort is the
auth sidecar when auth is on), so forte drop subdomains flow through the sidecar and
are Forte-login gated exactly like the admin root.

priority:1 (LOW) is load-bearing: Traefik orders routers by rule-length by default,
and this regex is longer than Host(`mcp.drop.forteapps.net`) — without the explicit
low priority it would STEAL mcp.drop (and apex) traffic into the web pod. priority:1
guarantees the exact Host() routers (mcp release + chart apex) always win.

Traefik v3 (chart 28.x) HostRegexp = Go RE2; verify the rendered router against
mcp./www./app./apex/<real-slug> before prod. Uses the wildcard-drop-forteapps-net-tls
secret from the Certificate added in the same branch.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/overlays/upc-dev/forte-drop/forte-drop-subdomains-ingressroute.yaml

@@ -0,0 +1,39 @@
+# Wildcard routing for per-slug forte drops: <slug>.drop.forteapps.net -> the forte-drop
+# web pod. The forteapp chart only emits a single exact Host(`drop.forteapps.net`) route
+# (the apex: admin + /api + public /shared drops), so this ADDITIVE IngressRoute adds the
+# wildcard. Kept in launchpad (forte-drop-specific) rather than the shared forteapp chart.
+#
+# It targets the SAME service the chart's route does — forte-drop-app:3000 — whose
+# targetPort is the auth sidecar (service.yaml: targetPort = auth.sidecarPort when auth is
+# on). So wildcard subdomains flow service:3000 -> sidecar -> app, i.e. they are Forte-login
+# gated exactly like the admin root. A forteOnly drop is therefore never served un-gated.
+#
+# priority: 1 (intentionally LOW). Traefik orders routers by rule-length by default, and the
+# regex string is longer than Host(`mcp.drop.forteapps.net`); without an explicit low
+# priority this regex would OUTRANK and STEAL mcp.drop.forteapps.net (and the apex) into the
+# web pod. priority:1 guarantees the exact Host() routers (mcp release, chart apex) always win;
+# only real per-slug subdomains fall through to here. The app's reserved-slug check
+# (mcp/www/api/admin/app) is a second line of defence.
+apiVersion: traefik.io/v1alpha1
+kind: IngressRoute
+metadata:
+  name: forte-drop-subdomains
+  namespace: forte-drop
+  labels:
+    app.kubernetes.io/name: forte-drop
+    app.kubernetes.io/part-of: apps
+    app.kubernetes.io/managed-by: argocd
+spec:
+  entryPoints:
+    - websecure
+  routes:
+    # Traefik v3 (chart 28.x) HostRegexp takes a Go RE2 pattern. Verify the rendered
+    # router against mcp./www./app./apex/<real-slug> before relying on it in prod.
+    - match: HostRegexp(`^[a-z0-9-]+\.drop\.forteapps\.net$`)
+      kind: Rule
+      priority: 1
+      services:
+        - name: forte-drop-app
+          port: 3000
+  tls:
+    secretName: wildcard-drop-forteapps-net-tls

apps/overlays/upc-dev/forte-drop/kustomization.yaml

@@ -6,3 +6,4 @@ resources:
 - forte-drop-pdb.yaml
 - forte-drop-secrets-sealed.yaml
 - wildcard-drop-tls-certificate.yaml
+- forte-drop-subdomains-ingressroute.yaml