fix(lint): declare telephony as optional uses-feature

[fluffyspace]

Summary

Unblocks ./gradlew lint on main. The AGP 9.0.1 → 9.2.0 bump (#788) was merged with a failing lint check, and every PR opened against current main now inherits the failure (e.g. #794).

Root cause

Lint 9.2.0 raises PermissionImpliesUnsupportedChromeOsHardware errors at AndroidManifest.xml:9 and :10 for CALL_PHONE and CALL_PRIVILEGED. Both permissions imply android.hardware.telephony, but the manifest never declared a matching <uses-feature> entry. The existing app/lint-baseline.xml was generated against lint 9.0.1 and doesn't cover these new checks (it also notes 4 stale entries that no longer apply under 9.2.0).

Fix

Add <uses-feature android:name="android.hardware.telephony" android:required="false" />. This is the fix lint suggests directly, and required="false" is correct here — the app can install on tablets and ChromeOS devices that lack telephony hardware. Dialer code paths that actually need telephony already gate at runtime via TelephonyManager / TelecomManager capability checks, so this does not change install or runtime behavior on devices that do have telephony.

The 4 stale baseline entries flagged by the new lint version are left for the existing fossifybot baseline-update workflow to clean up — they're warnings, not errors, and don't fail the build.

Test plan

• ./gradlew lint passes locally on main after the change
• Install on a phone — dialer still works as before (no manifest filter excludes it)
• Verify the app still appears in Play Store / install lists for tablets that lack telephony (would be excluded if required="true")