ci: remove old .gitea workflows - use .forgejo only

The .gitea/ workflows were outdated and caused conflicts:
- Used runs-on: rust, golang (non-existent runners)
- Complex docker:27-cli setup with TLS (fragile)
- Different secret variable names (FORGEJO_REGISTRY_TOKEN vs REGISTRY_PAT)
- No tests before build

.forgejo/workflows/build.yaml is the clean, working version:
- Simplified docker commands
- Proper runner: docker
- Tests run first
- Cleanup on failure
- No hanging processes

.dockerignore

@@ -1,28 +1,12 @@
-# Build artifacts
-target/
-*.rs.bk
-
-# Version control
-.git/
+.git
 .gitignore
-
-# IDE
-.idea/
-.vscode/
-*.swp
-
-# CI
-.github/
-.forgejo/
-
-# Documentation
 *.md
-!README.md
-
-# Tests (keep for build cache, exclude from runtime)
-tests/
-fixtures/
-
-# Logs
-log/
-*.log
+__pycache__
+*.pyc
+.env.local
+.venv
+venv/
+.pytest_cache
+.coverage
+htmlcov
+.DS_Store