fix(direct-edit): route off-server links out of the editor WebView

[jim-daf]

Closes #3191.

The NoteDirectEditFragment WebView loads the Nextcloud Text editor for the user's account but does not override shouldOverrideUrlLoading. Any link the editor renders (a markdown link to another site, a mailto: in a frontmatter table, a mention to a user on a different Nextcloud server) navigates the editor WebView itself, which drops the user out of the edit session.

Change

Override shouldOverrideUrlLoading. Keep navigations whose URL starts with the current account URL inside the WebView (so server-internal links the editor produces continue to work). Route everything else out via Intent.ACTION_VIEW. Wrap the launch in try/catch (ActivityNotFoundException) so a missing handler does not crash the Fragment:

override fun shouldOverrideUrlLoading(view: WebView?, request: WebResourceRequest?): Boolean {
    val url = request?.url ?: return false
    val scheme = url.scheme?.lowercase()
    val accountUrl = runCatching { account.url }.getOrNull()
    if ((scheme == "http" || scheme == "https") &&
        accountUrl != null && url.toString().startsWith(accountUrl)
    ) {
        return false
    }
    return try {
        val intent = Intent(Intent.ACTION_VIEW, url).apply {
            addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
        }
        startActivity(intent)
        true
    } catch (e: ActivityNotFoundException) {
        Log.w(TAG, "No app available to open $url", e)
        true
    }
}

The runCatching around account.url is so a transient access failure here cannot crash the WebViewClient callback. If the account URL is not available we just fall through to the external-route branch instead of blowing up.

Behaviour

• Same-server https link inside the editor (the case the editor actually produces): unchanged, stays in the WebView.
• External https link tapped from a note: opens in the system browser.
• mailto:, tel:, intent: link tapped from a note: opens in the matching system app.
• No handler installed: warning logged, no crash.

[codacy-production]

Not up to standards ⛔

🔴 Issues 1 minor

Alerts:
⚠ 1 issue (≤ 0 issues of at least minor severity)

Results:
1 new issue

Category	Results
Complexity	1 minor

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🟢 Metrics 0 duplication

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Duplication	0

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