Amber never appeared for delete/accept-invite/zap because Capacitor's default
WebView silently drops JS-initiated intent:/nostrsigner: navigations — the
request that opens Amber never reached the OS. Login worked only because it
uses the plugin's native startActivityForResult.
Add a custom MainActivity (android-templates/MainActivity.java) that overrides
shouldOverrideUrlLoading to launch intent:/nostrsigner: URLs via startActivity()
— a real native launch that opens Amber on GrapheneOS, matching login. Injected
into the generated android/ project at build time by inject-main-activity.mjs,
wired into android:build/sync/init. Simplify the JS launcher to navigate the
WebView (now intercepted natively). Bump to 1.2.8.
Co-authored-by: shakespeare.diy <assistant@shakespeare.diy>