Remove SOPS-encrypted authkey secret from Kustomize

Flux can't decrypt SOPS files in this setup. The secret will be
created manually on the cluster and won't be garbage collected by
Flux since it's not in the Kustomization resources.

infrastructure/controllers/base/tailscale/authkey-secret.enc.yaml

@@ -1,23 +0,0 @@
-apiVersion: ENC[AES256_GCM,data:RnI=,iv:8XkB3DGqi1C/kasS5GiQYudUFBMCA39P47f6ZrGXFfU=,tag:RbW4+ZJy23on1VHiVzB97A==,type:str]
-kind: ENC[AES256_GCM,data:vQxp8Yye,iv:NTnSCRy/ojgI6YxiNQ5hGTyyc6oI/bBXellOT3zPHC4=,tag:DyarSVGeW4V/ZWpgIGSprg==,type:str]
-metadata:
-    name: ENC[AES256_GCM,data:cqxm72lY889Hep3e4gvIGczUbg6b07ztbDw=,iv:EdtJiYsDOr0JI03Q1ppcUeR6mAiWCAoGcDgoeSuBWJc=,tag:hbNuhZ/2ADJ8JbB04IDpyQ==,type:str]
-    namespace: ENC[AES256_GCM,data:F5yrzxvlhG7r,iv:Bo6KQ5Jw//ujusHAKeFgbQZv9fiEjVGAcg2NfQoKkRQ=,tag:/7thf1cUYiXGpyJg+sB3sw==,type:str]
-type: ENC[AES256_GCM,data:gub4U7je,iv:9+2u9x1CTCorIp4o0f9RkmQQxmFFZzzamIFT4lvv3k4=,tag:SfHYbfwTCRnS9BXggD/lNg==,type:str]
-data:
-    authkey: ENC[AES256_GCM,data:MECFadN0uzQGUvHeTrFEF3DU4HhkvksqSu1XXUs4whDhvlHduwCsCpHSQIRP4TkEFmPnufaKwc3/PKNi82/h2EzA0p8ZsTlB5MHBS1xyk+FLZn6X,iv:+kyMjGtN+Snh0Gs4sGe+UOHTLHtMGODDkjDCYUnLpeA=,tag:29vMCubpg3hlw18/26azzQ==,type:str]
-sops:
-    age:
-        - recipient: age1uuxf066xuuqgvjppxfcmqkwfcufnwp3wcwnl9h20g9k4l8nkw9jsaungf7
-          enc: |
-            -----BEGIN AGE ENCRYPTED FILE-----
-            YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSBiWFVseVR2ODNrUHJkUXp1
-            eis0dmRhVTE1Z1lBME0vL3U1ektWQXBxY0JzClljNG9Tb0pHc2EzV2oySk1nd2Q0
-            elgxdlpYK2JyOXR3SXdTSGJOR1ZHTUkKLS0tIEdDMUMzWDJ4VmZkN2Nxb1hCV1pS
-            bTJCNEpKWDhFS1lPNFNhZVNIdnZQRHcKr+RoZ8Aci5qx31XLgARMnuMOe9rYJa74
-            l0n1wSF6nO2u+TFEJ4CCSVZ8KiiZXgj1SI5RH0lB45RDX5TgiOsMVA==
-            -----END AGE ENCRYPTED FILE-----
-    lastmodified: "2026-05-04T03:09:08Z"
-    mac: ENC[AES256_GCM,data:XZUchEgndlDyUK9jUazTlBNqmtLe1NfSy2PR8MUsglcEfuGLopaORCsYBkINC5VfRiX7bxu9jEY7nlxwUNng8zHO6RVYo2c5l7ocbtbGafLcXmjUyVB1un2koMWZnk10PTKxq3+Tda1KztQ8+zvmdAZYsJFU8gyRuH5L5dK5B2o=,iv:uTOP9ByQIYUJXVdafgwE1XeR983QVHDjNDehVhYEEkk=,tag:HuV1QR6mav9SPE9eUQGrFA==,type:str]
-    unencrypted_suffix: _unencrypted
-    version: 3.12.2

infrastructure/controllers/base/tailscale/kustomization.yaml

@@ -4,7 +4,6 @@ resources:
   - namespace.yaml
   - repository.yaml
   - release-operator.yaml
-  - authkey-secret.enc.yaml
   - dummy0auth.yaml
  # - tsproxy-rtx6000.yaml