app-email: smtp_mapping for vaultwarden + mealie

Vaultwarden via STARTTLS (accepts self-signed shim cert); Mealie via plaintext
(NONE) — no accept-invalid-cert option, spike-validated mode. Compose files
reference injected ${SMTP_*}. README documents the pattern.

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

templates/vaultwarden/.felhom.yml

@@ -84,3 +84,21 @@ healthcheck:
       path: "/alive"
       expect:
         status: 200
+
+# --- App-email mapping (apps → in-controller shim → hub → Resend) ---
+# When app-email is on (global toggle + this app's per-app toggle), the controller injects
+# the relay SMTP settings: host = the on-box shim, port = 2525, From = vaultwarden@felhom.eu.
+# Vaultwarden uses STARTTLS to the shim and accepts its self-signed cert
+# (SMTP_ACCEPT_INVALID_CERTS/HOSTNAMES). SMTP_USERNAME/SMTP_PASSWORD are intentionally left
+# unset — the shim accepts no-auth on the Docker network and holds no Resend key.
+smtp_mapping:
+  host_var: SMTP_HOST
+  port_var: SMTP_PORT
+  security_var: SMTP_SECURITY
+  security_value: starttls
+  from_var: SMTP_FROM
+  from_name_var: SMTP_FROM_NAME
+  from_local: vaultwarden
+  extra:
+    SMTP_ACCEPT_INVALID_CERTS: "true"
+    SMTP_ACCEPT_INVALID_HOSTNAMES: "true"