feat(server): REST + MCP routes (REST on :8310)

server.go

@@ -0,0 +1,28 @@
+package main
+
+import (
+	"net/http"
+)
+
+// Server — the HTTP/MCP server. Both surfaces (REST on :8310, MCP on :8320)
+// share the same Store.
+type Server struct {
+	store *Store
+}
+
+func NewServer(store *Store) *Server {
+	return &Server{store: store}
+}
+
+// Routes — the REST API surface. Per docs/API.md.
+func (s *Server) Routes() *http.ServeMux {
+	mux := http.NewServeMux()
+	mux.HandleFunc("GET /api/healthz", s.handleHealth)
+	mux.HandleFunc("GET /api/posts", s.handleListPosts)
+	mux.HandleFunc("POST /api/posts", s.handleCreatePost)
+	mux.HandleFunc("POST /api/authors", s.handleUpsertAuthor)
+	mux.HandleFunc("POST /api/channels", s.handleUpsertChannel)
+	mux.HandleFunc("GET /api/posts/{id}", s.handleGetPost)
+	mux.HandleFunc("POST /api/posts/{id}/comments", s.handleCreateComment)
+	return mux
+}