docs: document environment variable support for API keys

Author: zaxx-q

CHANGELOG.md

@@ -1,5 +1,14 @@
 # Changelog
 
+## [4.3.1] - 2026-02-14
+
+### Fixes
+
+- **Internal**: Renamed internal references to `AIPromptBridge.exe` (Console) and `AIPromptBridge-NoConsole.exe` (GUI)
+- **System Tray**: Fix application restart logic to correctly handle both launcher-based and source-based execution modes.
+- **UX**: Added a native Windows error dialog when attempting to run the internal binary directly.
+- **Audio Tool**: Switched from print statements to proper logging for cleaner output and better diagnostics.
+
 ## [4.3.0] - 2026-02-14
 
 ### New Features

README.md

@@ -222,6 +222,10 @@ For advanced users, configuration files are stored in the application root:
 - If one key hits rate limits, the next one is used automatically
 - The system tracks exhausted keys and skips them
 - Keys rotate on: 429 (rate limit), 401/402/403 (auth errors), empty responses
+- **Security**: You can also provide keys via Environment Variables instead of `config.ini`:
+  - `GEMINI_API_KEY`
+  - `OPENROUTER_API_KEY`
+  - `CUSTOM_API_KEY`
 
 ## 🔧 Command Line Options