feat: scaffold project with config, store, health endpoint, CI, and Dockerfile

Phase 1 of foreman: initialize the Go module, project layout, and core
infrastructure. Includes env-based configuration (FOREMAN_* namespace),
SQLite-backed durable job queue with WAL mode via modernc.org/sqlite,
stdlib HTTP server with /healthz and optional bearer-token auth middleware,
subcommand dispatch (serve + stubs), Gitea CI workflow, multi-stage
distroless Dockerfile, and comprehensive tests for all packages.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.gitignore

@@ -20,6 +20,13 @@ coverage.*
 .env.local
 *.local
 
+# Vendor
+vendor/
+
+# Go workspace
+go.work
+go.work.sum
+
 # Editor / OS cruft
 .DS_Store
 .idea/