Slice 1: build green, MVP core flow

- New agentlib module (gitutil + deployer with NewGo / NewPHP) replaces
  agent-micro/internal so both agents can share it (Go's internal/ rule
  was blocking agent-gateway from importing agent-micro's packages).
- Migrate agents from legacy github.com/docker/docker/client to the
  current github.com/moby/moby/client v0.5.0 / moby/moby/api v1.55.0.
- Fix compile errors in the original committed code: missing
  gorilla/websocket import in control-plane/internal/ws/handlers.go,
  unaliased dockerclient reference, wrong SQLite driver name
  (sqlite3 -> sqlite), Dialer.Dial 3-return-value mismatch.
- scripts/build.sh: Go 1.23 -> 1.24, apk add git, safe.directory for
  bind-mounted host tree, chmod inside container (host can't chmod
  files owned by container root).
- README and REQUIREMENTS updated to reflect the actual architecture
  (Go + SQLite, no Spring Boot, moby SDK, per-deploy no image build)
  with a per-feature status checklist at the end of REQUIREMENTS.

control-plane/internal/store/store.go

@@ -30,7 +30,7 @@ func Open(dir string) (*Store, error) {
 	if err := os.MkdirAll(filepath.Join(dir, "logs"), 0o755); err != nil {
 		return nil, err
 	}
-	db, err := sql.Open("sqlite3", filepath.Join(dir, "sdp.db"))
+	db, err := sql.Open("sqlite", filepath.Join(dir, "sdp.db"))
 	if err != nil {
 		return nil, err
 	}