refactor: remove /v1/gemini endpoint, replaced by /v1beta routes

- Delete handle_gemini handler (identical to handle_gemini_v1beta)
- Remove /v1/gemini route from router
- Update root handler service name to zerogravity
- Clean all doc references

src/api/gemini.rs

@@ -1,7 +1,6 @@
 //! Gemini-native endpoint — zero-translation tool call passthrough.
 //!
 //! Routes:
-//!   POST /v1/gemini                                  (custom, stream via body flag)
 //!   POST /v1beta/models/{model}:generateContent      (sync, official Gemini API path)
 //!   POST /v1beta/models/{model}:streamGenerateContent (stream, official Gemini API path)
 //!
@@ -118,13 +117,7 @@ async fn build_usage_metadata(
     }
 }
 
-/// POST /v1/gemini — simple custom endpoint
-pub(crate) async fn handle_gemini(
-    State(state): State<Arc<AppState>>,
-    Json(body): Json<GeminiRequest>,
-) -> axum::response::Response {
-    handle_gemini_inner(state, body).await
-}
+
 
 /// POST /v1beta/*path — handles both :generateContent and :streamGenerateContent
 ///
@@ -173,7 +166,7 @@ async fn handle_gemini_inner(
     body: GeminiRequest,
 ) -> axum::response::Response {
     info!(
-        "POST /v1/gemini model={} stream={}",
+        "POST /v1beta/gemini model={} stream={}",
         body.model.as_deref().unwrap_or(DEFAULT_MODEL),
         body.stream
     );

src/api/mod.rs

@@ -48,7 +48,6 @@ pub fn router(state: Arc<AppState>) -> Router {
             "/v1/chat/completions",
             post(completions::handle_completions),
         )
-        .route("/v1/gemini", post(gemini::handle_gemini))
         .route(
             "/v1beta/{*path}",
             post(gemini::handle_gemini_v1beta),
@@ -72,7 +71,7 @@ pub fn router(state: Arc<AppState>) -> Router {
 
 async fn handle_root() -> Json<serde_json::Value> {
     Json(serde_json::json!({
-        "service": "antigravity-openai-proxy",
+        "service": "zerogravity",
         "version": "3.3.0",
         "runtime": "rust",
         "endpoints": [