feat(forgejo): enable SMTP email notifications via Gmail

- mailer config: smtp+starttls to smtp.gmail.com:587
- SMTP creds via forgejo-smtp secret (SOPS-encrypted, Gmail App Password)
- Env var injection: GITEA__MAILER__USER/PASSWD from secret
- Enables CI completion emails, password reset, repo notifications

k8s/argocd/secrets/forgejo-smtp-secrets.enc.yaml

@@ -0,0 +1,24 @@
+apiVersion: ENC[AES256_GCM,data:uS8=,iv:EEoo9U+C244eAJMSTOQVkf5AE6BeHrc5DWPjtWnPRdk=,tag:H+YmBSGvcON3wh0p22LXDQ==,type:str]
+kind: ENC[AES256_GCM,data:j1/PFkTS,iv:ja4q8X+nzE/ZczwcY+Qe2DnnsxG64W1fkRPQvOaoqvA=,tag:WiilMGagudEKUlc2JdbGyg==,type:str]
+metadata:
+    name: ENC[AES256_GCM,data:J9iAIHboMyHu6xn/,iv:p3z3uzlkM7VDzOT3WDCelCdZ2t+QqSPmFtqYfvXPQMs=,tag:rKRtpUexVkuZKOJ34a0Xjw==,type:str]
+    namespace: ENC[AES256_GCM,data:su0FvA==,iv:6SPvwxZ/4aoL0Z07zdPC9r6L7HOHuKv3RodXpVcii04=,tag:njwkj+yvSgN8sliJP8T/Kw==,type:str]
+type: ENC[AES256_GCM,data:Qd6WJN1c,iv:M3fc78LvemcEbWzesuYeQ/GZyIOl7Eg/0EmUe3p0qAk=,tag:Tnzwewn0vwdowxy/EyuPdA==,type:str]
+stringData:
+    user: ENC[AES256_GCM,data:/Z7gPrsTUZOLzfoZ8cZGD10wrZE=,iv:0ydBSeq+yHB2b1J4W7FwIv55Eh+N3qfQ6Q7PwoUAvYo=,tag:CO19F8nElaYZyFiFR6N/Tg==,type:str]
+    password: ENC[AES256_GCM,data:AOl4StpeQIHSLX+oEFnkfg==,iv:mYsZ+5sum6YqyUPndtPCniTraxldKc803ULlKs8Gsaw=,tag:hK3w51ifZ/omAL7XDf8seg==,type:str]
+sops:
+    age:
+        - enc: |
+            -----BEGIN AGE ENCRYPTED FILE-----
+            YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSBaMlhKVEM2bFdFOFAwV1lp
+            WUd6SEN4ZTF1TEpGYXhOYmJLK0tpcWZyc2w4ClVzZmI2Qk1KUnV1OXpyTEV2WWFa
+            VlJ2eHRSaEhqUnA2dUJVbWJUcEgxcFkKLS0tIG9IaFVnenNpSFRzdStiWjJvakVL
+            aDk2bTZGR3Zya3ROUS9vd1hEQVRFaG8KbeXA6IebHEaB79N6u795336aHesHOgzO
+            uZvvBUzSBy3t3jfFk8bJP4aH79I33Ha2eK5rsvdsiv/orwCMXUINKg==
+            -----END AGE ENCRYPTED FILE-----
+          recipient: age1e5fq3hwxy78psus2nfvmtmua36g0u3suk78ephw6246l974d2utsvn0hla
+    lastmodified: "2026-09-12T21:00:46Z"
+    mac: ENC[AES256_GCM,data:DjzPtR+Ueihh166Bvd3jCLtZFQdrvrxOoF87cv6lxKGWPEptT5vbw/EfuIFJBb6lvEJFDWKRC/r5ASdGwComYsPn0DZs4BPCzeKBtLfP9K2OGCXnAC7eGqt4mzMrrW0CQd1QSGcuXw8CY7uJGkMPGPKe3/0mQWiis2OSpHxTM18=,iv:/QqSEFU9RuX9z5Z6aSaD7KlP/cgGTOYvTH+VJOnDTYM=,tag:yFbFXn+iWqQZx7wW4dKppg==,type:str]
+    unencrypted_suffix: _unencrypted
+    version: 3.13.2

k8s/argocd/secrets/secret-generator.yaml

@@ -30,3 +30,4 @@ files:
   - gotify-admin-secrets.enc.yaml
   - gotify-tokens-secrets.enc.yaml
   - gotify-smtp-secrets.enc.yaml
+  - forgejo-smtp-secrets.enc.yaml

k8s/bootstrap/phase3-forgejo/forgejo-values.yaml

@@ -80,6 +80,14 @@ gitea:
     actions:
       ENABLED: true
 
+    mailer:
+      ENABLED: true
+      PROTOCOL: smtp+starttls
+      SMTP_ADDR: smtp.gmail.com
+      SMTP_PORT: 587
+      FROM: "Forgejo <[email protected]>"
+      # USER and PASSWD injected via env vars below (GITEA__MAILER__USER, GITEA__MAILER__PASSWD)
+
 # Persistence (shared storage for repos)
 persistence:
   enabled: true
@@ -148,3 +156,13 @@ deployment:
         secretKeyRef:
           name: forgejo-db-app
           key: password
+    - name: GITEA__MAILER__USER
+      valueFrom:
+        secretKeyRef:
+          name: forgejo-smtp
+          key: user
+    - name: GITEA__MAILER__PASSWD
+      valueFrom:
+        secretKeyRef:
+          name: forgejo-smtp
+          key: password