Stop forcing external links into the native WebView

[Copilot]

Mobile app links were opening inside the embedded WebView instead of the system browser. This updates Capacitor navigation policy so external HTTP(S) destinations are no longer broadly whitelisted for in-app loading.

• Capacitor navigation policy

  • Removed wildcard allowNavigation from capacitor.config.ts.
  • This avoids treating arbitrary web hosts as in-app navigable targets.

• Android runtime override

  • Removed the matching wildcard setAllowNavigation(...) override in MainActivity.
  • Prevents Android native boot config from reintroducing the same broad in-app navigation behavior.

• Regression coverage

  • Added a focused config test asserting server.allowNavigation is unset.

// capacitor.config.ts
server: {
  cleartext: true,
}