docs(httpserver): correct tier from 4 to 3

httpserver depends on launcher (Tier 2), placing it at Tier 3.
With launcher corrected from Tier 5 to Tier 2, httpserver's tier
drops accordingly.

README.md

@@ -0,0 +1,67 @@
+# httpserver
+
+Lifecycle-managed HTTP server built on [chi](https://github.com/go-chi/chi) that integrates with the launcher component model.
+
+## Features
+
+- Implements `launcher.Component` (`OnInit` / `OnStart` / `OnStop`)
+- Embeds `chi.Router` — full routing API exposed directly on the component
+- Graceful shutdown with configurable timeouts
+- No middleware installed by default — compose your stack with `WithMiddleware`
+
+## Installation
+
+```
+require code.nochebuena.dev/go/httpserver v0.1.0
+```
+
+## Usage
+
+```go
+srv := httpserver.New(logger, cfg,
+    httpserver.WithMiddleware(
+        httpmw.Recover(),
+        httpmw.CORS([]string{"*"}),
+        httpmw.RequestID(uuid.NewString),
+        httpmw.RequestLogger(logger),
+    ),
+)
+
+// Register routes directly on srv — it is a chi.Router.
+srv.Get("/health", health.NewHandler(logger, db, cache))
+
+srv.Route("/api/v1", func(r chi.Router) {
+    r.Use(httpauth.AuthMiddleware(firebaseClient, nil))
+    r.Get("/orders/{id}", httputil.Handle(validator, svc.GetOrder))
+})
+
+lc := launcher.New(logger)
+lc.Append(db, cache, srv)
+if err := lc.Run(); err != nil {
+    log.Fatal(err)
+}
+```
+
+## Config
+
+| Field | Env var | Default | Description |
+|---|---|---|---|
+| `Host` | `SERVER_HOST` | `0.0.0.0` | Bind address |
+| `Port` | `SERVER_PORT` | `8080` | Listen port |
+| `ReadTimeout` | `SERVER_READ_TIMEOUT` | `5s` | Max time to read request |
+| `WriteTimeout` | `SERVER_WRITE_TIMEOUT` | `10s` | Max time to write response |
+| `IdleTimeout` | `SERVER_IDLE_TIMEOUT` | `120s` | Keep-alive idle timeout |
+
+## Options
+
+| Option | Description |
+|---|---|
+| `WithMiddleware(mw ...func(http.Handler) http.Handler)` | Applies middleware to the root router during `OnInit` |
+
+## Lifecycle
+
+| Phase | Action |
+|---|---|
+| `OnInit` | Applies registered middleware to the router |
+| `OnStart` | Starts `net/http.Server` in a background goroutine |
+| `OnStop` | Graceful shutdown — waits up to 10s for in-flight requests |