fix(android): open Activity view with device hostname, not unknown

[TimeToBuildBob]

Problem

v0.14.0b2 user report on #247: the hamburger-menu Activity entry works, but the left-swipe drawer Activity item opens the same page with hostname unknown and default (non-Android) visualizations.

Cause: the drawer item and notification-tap path hardcoded /#/activity/unknown/. The in-app hamburger builds /activity/<real-hostname> from buckets, so it gets Android views. unknown is a sentinel (stopwatch / missing host), not a device.

Fix

• Build /#/activity/<sanitized-device-hostname>/ using the same hostname as Android bucket creation (Settings.Global.DEVICE_NAME / Build.DEVICE).
• One helper for that sanitization, shared by RustInterface and SyncInterface.

Does not close #247. Remaining there: sync UX/discoverability, last-sync / success-fail UI, category-import save persistence. Sync 401 is #249.

Testing

JAVA_HOME=/opt/android-studio/jbr ANDROID_HOME=/home/bob/Android/Sdk \
  ./gradlew :mobile:testDebugUnitTest \
  --tests net.activitywatch.android.MainActivityNavigationTest \
  --tests net.activitywatch.android.DeviceHostnameTest \
  --tests net.activitywatch.android.DashboardAuthTest \
  --no-daemon

Passed (14 tests).

[greptile-apps]

Greptile Summary

The PR replaces hardcoded unknown Activity routes with the same sanitized device hostname used by Android buckets and synchronization.

• Adds a shared helper for resolving and sanitizing the Android device hostname.
• Uses the resolved hostname for drawer and notification Activity navigation.
• Refactors server and synchronization interfaces to share the helper.
• Adds unit coverage for hostname sanitization and Activity-route generation.

Confidence Score: 5/5

The PR appears safe to merge, with device-hostname routing consistently applied across the affected navigation, bucket, and synchronization paths.

The shared helper preserves existing hostname normalization while replacing the erroneous hardcoded Activity host, and the changed navigation paths continue to construct authenticated local dashboard URLs.

Important Files Changed

Filename	Overview
mobile/src/main/java/net/activitywatch/android/DeviceHostname.kt	Introduces a shared hostname resolver while preserving the previous normalization and fallback behavior.
mobile/src/main/java/net/activitywatch/android/MainActivity.kt	Routes all Activity navigation entry points to the sanitized device hostname while retaining dashboard authentication.
mobile/src/main/java/net/activitywatch/android/RustInterface.kt	Replaces duplicated device-name normalization with the shared helper without changing the effective bucket identity contract.
mobile/src/main/java/net/activitywatch/android/SyncInterface.kt	Reuses the shared hostname helper for native synchronization without changing effective behavior.
mobile/src/test/java/net/activitywatch/android/DeviceHostnameTest.kt	Covers empty, invalid, mixed-case, spaced, hyphenated, and underscored hostname inputs.
mobile/src/test/java/net/activitywatch/android/MainActivityNavigationTest.kt	Verifies dashboard defaults and hostname-aware Activity route construction.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart LR
    A[Android device name] --> B[deviceHostname]
    B --> C[sanitizeDeviceHostname]
    C --> D[Bucket hostname]
    C --> E[Sync hostname]
    C --> F[Activity route]
    F --> G[Embedded ActivityWatch dashboard]

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_{Reviews (1): Last reviewed commit: "fix(android): open Activity view with de..." | Re-trigger Greptile}

[TimeToBuildBob]

Greptile is 5/5 and the unit-test job passed. The Android 29 E2E job is still running, so no merge action is available yet; this repo is maintainer-merge only for Bob.

[TimeToBuildBob]

CI-green and mergeable (Greptile 5/5) — waiting only on a maintainer click.

This PR is ready to merge, but the bot has pull-only access to this repo and can't self-merge — surfacing it here so it isn't lost. The monitoring loop will stop re-flagging it now that this note is posted.