[codex] Stabilize Atlas Gemma 4 runtime

[Devil1716]

What changed

• unified the app around a resilient Gemma 4 download manager with resume, verification markers, retry handling, and file-backed diagnostics
• hardened the planner/executor/verifier loop so Atlas retries incomplete steps, confirms task completion, and logs failures instead of crashing
• refreshed onboarding and main surfaces into the new Atlas branding with a cleaner Manus-like visual direction
• updated release automation and bumped the app to v0.5.9

Why

• model download failures could crash the app during onboarding and leave stale partial files behind
• the on-device agent needed stronger completion guarantees and more reliable reasoning behavior for longer tasks
• the release needed a fresh downloadable APK tied to the validated reliability fixes

Validation

• ./gradlew.bat clean testDebugUnitTest --console=plain
• ./gradlew.bat connectedDebugAndroidTest --console=plain
• ./gradlew.bat assembleRelease --console=plain
• manual emulator smoke test on the release APK: launched Atlas onboarding, started Gemma 4 download, confirmed UI stayed alive and crash buffer remained empty