feat(wiki): wire up the wikijs-postgres-secret (created by sorb)

The SOPS-encrypted secret existed locally but was untracked and not in the
kustomization, so Flux never applied it and both wiki pods stayed in
CreateContainerConfigError (secret not found). Add it to resources and commit.
Values not read; age recipient matches .sops.yaml so Flux can decrypt.

apps/production/kustomization.yaml

@@ -53,7 +53,8 @@ resources:
   # Client-seitiger Scan-Dienst für verschlüsselte Räume (Issue #19-Erweiterung)
   - clamav-http-scanner.yaml
   - concierge-bot.yaml
-  # Wiki.js (Plattform-Wiki, ADR-0014, #0048) - wartet auf wikijs-postgres-secret
+  # Wiki.js (Plattform-Wiki, ADR-0014, #0048)
+  - wikijs-postgres-secret.yaml   # SOPS, von sorb angelegt
   - wikijs-postgres.yaml
   - wikijs.yaml
   - wiki-ingress.yaml

apps/production/wikijs-postgres-secret.yaml

@@ -0,0 +1,23 @@
+apiVersion: v1
+data:
+    password: ENC[AES256_GCM,data:ALT8e6Z6nZXHWkB6w3ZtkW7z14VAN0LpFITlCQBiJ9Up0O0dVhikfseCygo=,iv:Pn6U3t5QCqnYZA2TAk/fQBnE7FITTVoNzyCzMA/Wo+w=,tag:KAHpwDDRN9bIzMkWFBooqQ==,type:str]
+    username: ENC[AES256_GCM,data:KJQbdaJXroo=,iv:0ZVry78Bg9WRW0+vR7Opib9McGC5pyHtaxXExyh9dAk=,tag:PJvI4tigyIDZc0ASLEvUFA==,type:str]
+kind: Secret
+metadata:
+    name: wikijs-postgres-secret
+    namespace: matrix
+sops:
+    age:
+        - enc: |
+            -----BEGIN AGE ENCRYPTED FILE-----
+            YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSBDY2xSYVl1R3M5SVI4UnR1
+            cFpZcXBLL2thdDdWRmtSa3kxM3FkRWIwRW1ZCk8xa25GbzVDQjlFNk0rcmUwcldJ
+            Z0JNVWhXQTY3VWlDYjFPQkFQM1FFRzgKLS0tIDkzME02K3hYTUFWNGpLY3N3emcr
+            OXhrd2pUSnpTU2ZUWHV2MnMzdUFVVlUKyrvbkRz4sM5FjdHbP0vdkqYlQZxr33c1
+            HDScKVKJ++RBXpP4+x7B6rjSiMsV0I8eT678IO3wz/qGugvrTTZt0w==
+            -----END AGE ENCRYPTED FILE-----
+          recipient: age14l0hwfqylwpemz5y2ghh2yxk0phszlnj3qlejhue0fw0kz3tmfgqdsjzdh
+    encrypted_regex: ^(data|stringData)$
+    lastmodified: "2026-08-12T19:16:30Z"
+    mac: ENC[AES256_GCM,data:3uz4TmPnSwNK3vmBmRzGtwl2qMxPMQDWEqxpwQ0AbTOpyCiLmhqh1/eIvH1qOQoV5RQMkfcGa0XF2dxb7Wr4S52m8E19zyOmw2HNHvUj9gt2IUGHBUm5nZ2Qd0fO38VTdRX+Eyv7y/brbz1+guXMOTAwAbEHh51oV7rc7cyRCQo=,iv:8Kl7qOyfF1AlEMIFTaBM7nXZDE6RhsPJjj9QbzIJ8ns=,tag:BtvI0TpoY339XfXcknTVDw==,type:str]
+    version: 3.13.3