Add initial Go server skeleton with HTTP handlers, middleware, job runner, and stubs

internal/http/README.md

@@ -0,0 +1,8 @@
+This folder contains HTTP handlers, router registration, and middleware.
+
+Key files:
+- `router.go` - registers routes and APIs.
+- `handlers.go` - small HTMX-based handlers for the dashboard and API.
+- `middleware.go` - request id, logging, placeholder auth and CSRF.
+
+Handlers should accept `*App` struct for dependency injection.