Fix firmware size limits and refresh CI compatibility checks

Compact the existing STM32 field arithmetic and ESP-NOW tail-frame storage without removing features or lowering memory reserves. Refresh power-saving fixtures and pin official-app tests to a published archive.

.github/workflows/run-unit-tests.yml

@@ -796,7 +796,7 @@ jobs:
         uses: actions/cache@v4
         with:
           path: ~/.cache/meshcore-tests
-          key: official-clients-84bc39a950735aaffa93d912556852a4c22e235d0cc4e4d04790113207f13a68-aff42ad8ef2b332f24d644ff6a783f8272a88ff2
+          key: official-clients-${{ hashFiles('test/test_official_app_compatibility.py', 'test/test_official_config_gui.py', 'test/test_official_web_console.py') }}
 
       - name: Verify stock app radio, Access Control and room compatibility
         run: |