ci: switch image registry from ghcr.io to git.farh.net

- Update REGISTRY env var to git.farh.net
- Use GITEA_TOKEN instead of GITHUB_TOKEN for docker login
- Use rename form for kustomize image updates (ghcr.io=git.farh.net/...)
- Remove GHA cache lines (not available on Gitea runners)

Refs: CAR-959

.github/workflows/ci.yml

@@ -16,7 +16,7 @@ permissions:
   security-events: write
 
 env:
-  REGISTRY: ghcr.io
+  REGISTRY: git.farh.net
   IMAGE_NAME: cartsnitch/auth
 
 jobs:
@@ -42,12 +42,12 @@ jobs:
           else BUILD_NUM=$(echo "$EXISTING" | sed "s/v${DATE_TAG}\.//"); VERSION="${DATE_TAG}.$((BUILD_NUM + 1))"; fi
           echo "version=$VERSION" >> "$GITHUB_OUTPUT"
 
-      - name: Log in to GHCR
+      - name: Log in to Gitea Container Registry
         uses: docker/login-action@v3
         with:
           registry: ${{ env.REGISTRY }}
           username: ${{ github.actor }}
-          password: ${{ secrets.GITHUB_TOKEN }}
+          password: ${{ secrets.GITEA_TOKEN }}
 
       - name: Extract metadata
         id: meta
@@ -66,8 +66,6 @@ jobs:
           push: true
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}
-          cache-from: type=gha
-          cache-to: type=gha,mode=max
 
       - name: Create git tag
         if: github.ref == 'refs/heads/main'
@@ -110,7 +108,7 @@ jobs:
       - name: Update auth image tag in dev overlay
         run: |
           cd infra/apps/overlays/dev
-          kustomize edit set image ghcr.io/cartsnitch/auth:${{ steps.tag.outputs.tag }}
+          kustomize edit set image ghcr.io/cartsnitch/auth=git.farh.net/cartsnitch/auth:${{ steps.tag.outputs.tag }}
 
       - name: Commit and push to infra
         run: |
@@ -158,7 +156,7 @@ jobs:
       - name: Update auth image tag in uat overlay
         run: |
           cd infra/apps/overlays/uat
-          kustomize edit set image ghcr.io/cartsnitch/auth:${{ steps.tag.outputs.tag }}
+          kustomize edit set image ghcr.io/cartsnitch/auth=git.farh.net/cartsnitch/auth:${{ steps.tag.outputs.tag }}
 
       - name: Commit and push to infra
         run: |