fix(help): preserve WebView state across home/resume (#136)

[jim-daf]

Closes #136.

The Help WebView lost its state on every Home press because onResume unconditionally cleared history and reloaded the start page. Returning to the app dropped the user back at helpindex.html regardless of what they had been reading or how far they had scrolled.

This change loads the start page once when the activity is created, persists the WebView snapshot in onSaveInstanceState, and restores it when the activity is recreated. onResume no longer touches navigation state.

if (savedInstanceState != null) {
    helpBrowser.restoreState(savedInstanceState);
} else {
    Intent intent = this.getIntent();
    startPage = assetPrefix + intent.getStringExtra("page");
    helpBrowser.loadUrl(startPage);
}

@Override
protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    if (helpBrowser != null) {
        helpBrowser.saveState(outState);
    }
}

[Copilot]

Pull request overview

Fixes the Help WebView navigation/scroll state being lost when the app is backgrounded (Home) and resumed, aligning behavior with Issue #136 by restoring the WebView snapshot instead of reloading the start page on every onResume.

Changes:

• Load the help start page only on fresh activity creation; otherwise restore the WebView state from savedInstanceState.
• Persist WebView state via onSaveInstanceState() and stop clearing history/reloading in onResume().

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[Copilot]

WebView.restoreState() can return null when there’s no WebView state in the Bundle. If that happens, the current code won’t load the start page and the WebView may stay blank. Consider checking the return value and falling back to loading the intent page when restore fails.

[Copilot]

startPage is now only assigned and immediately used in this branch. Consider making it a local variable (or removing the field entirely) to avoid keeping an unused instance field that can be null in the restored-state path.