feat(ide): add GEMINI_CLI_IDE_PID env var to override IDE process detection (#15842)

Co-authored-by: Adib234 <30782825+Adib234@users.noreply.github.com>

docs/ide-integration/index.md

@@ -170,6 +170,20 @@ messages and how to resolve them.
   - **Solution:** Run `/ide enable` to try and reconnect. If the issue
     continues, open a new terminal window or restart your IDE.
 
+### Manual PID override
+
+If automatic IDE detection fails, or if you are running Gemini CLI in a
+standalone terminal and want to manually associate it with a specific IDE
+instance, you can set the `GEMINI_CLI_IDE_PID` environment variable to the
+process ID (PID) of your IDE.
+
+```bash
+export GEMINI_CLI_IDE_PID=12345
+```
+
+When this variable is set, Gemini CLI will skip automatic detection and attempt
+to connect using the provided PID.
+
 ### Configuration errors
 
 - **Message:**

docs/reference/configuration.md

@@ -1274,6 +1274,11 @@ the `advanced.excludedEnvVars` setting in your `settings.json` file.
   - Specifies the default Gemini model to use.
   - Overrides the hardcoded default
   - Example: `export GEMINI_MODEL="gemini-3-flash-preview"`
+- **`GEMINI_CLI_IDE_PID`**:
+  - Manually specifies the PID of the IDE process to use for integration. This
+    is useful when running Gemini CLI in a standalone terminal while still
+    wanting to associate it with a specific IDE instance.
+  - Overrides the automatic IDE detection logic.
 - **`GEMINI_CLI_HOME`**:
   - Specifies the root directory for Gemini CLI's user-level configuration and
     storage.