GRM-101: refactor: rename REPO_TOKEN to CI_GITEA_TOKEN, consolidate env vars

.env.example

@@ -15,7 +15,7 @@ GITEA_REGISTRATION_TOKEN=your-registration-token
 # If set, API checks are performed as a bonus but do NOT affect pass/fail.
 # Required scopes: read:user, read:repository, read:admin (or just "admin")
 # Generate token at: Settings → Applications → Generate New Token
-# REPO_TOKEN=your-admin-api-token
+# CI_GITEA_TOKEN=your-admin-api-token
 
 # Integration test API retries (optional, default: 3).
 # Number of times to retry API checks waiting for runner to appear.
@@ -39,7 +39,7 @@ GITEA_REGISTRATION_TOKEN=your-registration-token
 
 # Gitea PyPI registry username (for private package access)
 # Used by PIP_INSTALL to configure PIP_EXTRA_INDEX_URL
-GITEA_REGISTRY_USERNAME=emil
+CI_GITEA_USERNAME=emil
 
 # devx configuration (GRM-specific overrides)
 # Task prefix for Vikunja task IDs