Add more androidDevice actions to the mobile-2 sample

[jebrans]

What this changes

• Adds composeEmail, shareText, openSettings, createCalendarEvent and
  playMusicFromSearch to androidDeviceSchema.ts and wires each one through
  AndroidDeviceAgent, WebSocketManager, ChatViewModel and MainActivity.
• Uses ACTION_SENDTO with a bare mailto: URI for composeEmail, so only
  mail apps resolve rather than every share target, and carries recipients as
  EXTRA_EMAIL/EXTRA_CC/EXTRA_BCC arrays instead of splicing them into the
  URI. A single unusable address fails the whole action, because a draft
  addressed to fewer people than the user asked for would look like success.
• Resolves the inner ACTION_SEND intent before wrapping it in
  Intent.createChooser for shareText. The chooser is a system activity that
  always resolves, so an unchecked wrap would report success on a device with
  no text handler.
• Restricts openSettings to a closed AndroidSettingsScreen enum mapped
  exhaustively to Settings.ACTION_* constants. The model never supplies a raw
  intent action string, appInfo is pinned to this app's own package, and the
  screens only display settings rather than toggling them.
• Adds createCalendarEvent as ACTION_INSERT on CalendarContract.Events,
  which opens the calendar app's pre-filled new-event editor and so needs no
  WRITE_CALENDAR permission. ISO-8601 times are resolved without java.time,
  since the module targets minSdk 24 with no core-library desugaring.
• Builds calendar offset zones from a raw integer offset via SimpleTimeZone
  rather than by formatting a GMT+hh:mm string. String.format is
  locale-sensitive, and under a locale with non-Latin digits
  TimeZone.getTimeZone cannot read the result and silently returns GMT,
  turning +05:30 into a five-and-a-half-hour shift with no error.
• Anchors all-day events at UTC midnight as CalendarContract requires, so a
  user in UTC+10 does not see them land a day early.
• Fails rather than guessing on an unknown music focus, an unknown settings
  screen, an all-day event that also carries a time of day, and an event
  spanning more than 366 days.
• Adds a <queries> entry for every new implicit intent. Without one, Android
  11+ package visibility makes resolveActivity return null and the action
  falsely reports that no app is available.
• Extends AndroidDeviceSchemaAssetTest to check that the settings-screen and
  music-focus unions in the schema match the Kotlin enums, so the two cannot
  drift apart silently.

Every action reaches the OS through the existing launchExternalIntent funnel,
keeping the current resolveActivity check, foreground-lifecycle check and
exception handling, and completing its callback exactly once. The ten existing
Tier-1 actions are unchanged.

Verification

Unit tests and the debug build completed successfully:

• gradlew testDebugUnitTest — 234 tests, 0 failures (previously 179).
• gradlew assembleDebug — successful.
• gradlew lintDebug — clean; the only findings are pre-existing
  informational items unrelated to this change.

Review confirmed:

• A GPT-5.3-Codex review reported no Critical or High findings. Its Medium
  finding (locale-sensitive offset formatting) and Low finding (fractional
  seconds rejected) are both fixed here, each with a regression test. The
  locale defect was reproduced on the JVM before and after the fix: +05:30
  resolved to offset 0 instead of 19800000.
• Hours-only ISO offsets such as +05 are now accepted, with a test.
• No new permissions are declared in AndroidManifest.xml.