fix: only fire browserClosed when the custom tab actually terminates

[OS-ruimoreiramendes]

⚠️ 🤖 AI-assisted PR with Claude

Description

Refactor the Custom Tabs flow so browserClosed fires only when the Custom Tab actually terminates. Uses ActivityResultLauncher in OSIABCustomTabsControllerActivity instead of inferring closure from TAB_HIDDEN in OSIABCustomTabsSessionHelper.

Files changed:

• OSIABCustomTabsControllerActivity — registers ActivityResultLauncher, launches the CCT from an intent extra, finishes only on the launcher result. Start animations preserved via ActivityOptionsCompat.makeCustomAnimation reconstructed from extras (exit animations travel inside the intent).
• OSIABCustomTabsRouterAdapter — builds the CCT intent up front and hands it to the controller activity; listens for EVENT_CUSTOM_TABS_DESTROYED to fire onBrowserFinished.
• OSIABCustomTabsSessionHelper — removed the TAB_HIDDEN interpretation and the isCustomTabsActivityOnTop / pendingTabHiddenEvent state. Only handles NAVIGATION_FINISHED → BrowserPageLoaded.

Context

CustomTabsCallback.onNavigationEvent(TAB_HIDDEN) fires on close, PiP minimize, home button, task switch — the previous heuristic couldn't disambiguate them and fired browserClosed prematurely (notably on PiP).

Same approach as @capacitor/browser #2561, which fixed the equivalent issue in capacitor-plugins#2554.

Type of changes

• Fix (non-breaking change which fixes an issue)
• Feature (non-breaking change which adds functionality)
• Refactor (cosmetic changes)
• Breaking change (change that would cause existing functionality to not work as expected)

Tests

Unit tests updated to match the new event flow.

Manually tested on a physical Android device using the example app of capacitor-os-inappbrowser, which uses an AAR of this PR:

• Open browser → close via back gesture / X button → browserFinished fires once
• Open browser → minimize to PiP → maximize → close → browserFinished fires once, only on close
• Open browser → send app to background → return to app → close browser → browserFinished fires once,
  only on close

Checklist

• Code follows code style of this project
• CHANGELOG.md file is correctly updated
• Changes require an update to the documentation
  • Documentation has been updated accordingly