fix: replace actions/checkout with direct git clone to preserve /git/ subpath

- Replace actions/checkout@v4 with git clone in both jobs
- Clone URL: https://x-access-token:${FORGEJO_TOKEN}@srvr.nu/git/jocke/bilhej.git
- The checkout action constructed https://srvr.nu/jocke/bilhej/ dropping the /git/ subpath
- FORGEJO_TOKEN is automatically injected by Forgejo at runtime
- Remove ineffective GITHUB_SERVER_URL env var

.forgejo/workflows/ci.yml

@@ -6,15 +6,15 @@ on:
   pull_request:
     branches: [master, develop]
 
-env:
-  GITHUB_SERVER_URL: https://srvr.nu/git
-
 jobs:
   lint-and-test:
     name: Lint, type check, unit tests, coverage
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - name: Checkout repository
+        run: |
+          git clone --depth 1 \
+            https://x-access-token:${FORGEJO_TOKEN}@srvr.nu/git/jocke/bilhej.git .
 
       - uses: actions/setup-node@v4
         with:
@@ -64,7 +64,10 @@ jobs:
       STRIPE_WEBHOOK_SECRET: whsec_fake
       STRIPE_PRICE_ID: price_fake
     steps:
-      - uses: actions/checkout@v4
+      - name: Checkout repository
+        run: |
+          git clone --depth 1 \
+            https://x-access-token:${FORGEJO_TOKEN}@srvr.nu/git/jocke/bilhej.git .
 
       - name: Run E2E test stack
         run: |