fix: smoke test leaks orphaned mock-forgejo.py processes (#196)

Add cleanup trap to smoke-init.sh that kills all mock-forgejo.py processes
on exit (success or failure). Also ensure cleanup at test start removes
any leftover processes from prior runs.

In .woodpecker/smoke-init.yml:
- Store the PID of the mock-forgejo.py background process
- Kill the process after smoke test completes

This prevents accumulation of orphaned Python processes that caused
OOM issues (2881 processes consuming 7.45GB RAM).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/smoke-init.sh

@@ -24,6 +24,8 @@ fail() { printf 'FAIL: %s\n' "$*" >&2; FAILED=1; }
 pass() { printf 'PASS: %s\n' "$*"; }
 
 cleanup() {
+  # Kill any leftover mock-forgejo.py processes by name
+  pkill -f "mock-forgejo.py" 2>/dev/null || true
   rm -rf "$MOCK_BIN" /tmp/smoke-test-repo \
          "${FACTORY_ROOT}/projects/smoke-repo.toml"
   # Restore .env only if we created the backup