Implement HTTP timeout configurations and enhance API documentation

- Added optional HTTP server timeout configurations (`HNHMAP_READ_TIMEOUT`, `HNHMAP_WRITE_TIMEOUT`, `HNHMAP_IDLE_TIMEOUT`) to `.env.example` and updated the server initialization in `main.go` to utilize these settings.
- Enhanced API documentation for the `rebuildZooms` endpoint to clarify its background processing and polling mechanism for status updates.
- Updated `configuration.md` to include new timeout environment variables for better configuration guidance.
- Improved error handling in the client for large request bodies, ensuring appropriate responses for oversized payloads.

internal/app/handlers/handlers_test.go

@@ -1,6 +1,7 @@
 package handlers_test
 
 import (
+	"bytes"
 	"context"
 	"encoding/json"
 	"errors"
@@ -677,3 +678,38 @@ func TestClientRouter_InvalidToken(t *testing.T) {
 		t.Fatalf("expected 401, got %d", rr.Code)
 	}
 }
+
+func TestClientRouter_PositionUpdate_BodyTooLarge(t *testing.T) {
+	env := newTestEnv(t)
+	env.createUser(t, "alice", "pass", app.Auths{app.AUTH_UPLOAD})
+	tokens := env.auth.GenerateTokenForUser(context.Background(), "alice")
+	if len(tokens) == 0 {
+		t.Fatal("expected token")
+	}
+	// Body larger than maxClientBodySize (2MB)
+	bigBody := bytes.Repeat([]byte("x"), 2*1024*1024+1)
+	req := httptest.NewRequest(http.MethodPost, "/client/"+tokens[0]+"/positionUpdate", bytes.NewReader(bigBody))
+	req.Header.Set("Content-Type", "application/json")
+	rr := httptest.NewRecorder()
+	env.h.ClientRouter(rr, req)
+	if rr.Code != http.StatusRequestEntityTooLarge {
+		t.Fatalf("expected 413, got %d: %s", rr.Code, rr.Body.String())
+	}
+}
+
+func TestClientRouter_MarkerUpdate_BodyTooLarge(t *testing.T) {
+	env := newTestEnv(t)
+	env.createUser(t, "alice", "pass", app.Auths{app.AUTH_UPLOAD})
+	tokens := env.auth.GenerateTokenForUser(context.Background(), "alice")
+	if len(tokens) == 0 {
+		t.Fatal("expected token")
+	}
+	bigBody := bytes.Repeat([]byte("x"), 2*1024*1024+1)
+	req := httptest.NewRequest(http.MethodPost, "/client/"+tokens[0]+"/markerUpdate", bytes.NewReader(bigBody))
+	req.Header.Set("Content-Type", "application/json")
+	rr := httptest.NewRecorder()
+	env.h.ClientRouter(rr, req)
+	if rr.Code != http.StatusRequestEntityTooLarge {
+		t.Fatalf("expected 413, got %d: %s", rr.Code, rr.Body.String())
+	}
+}