Remove legacy Direct Message privacy UI

Removes the "Direct message privacy" section from the profile modal's Messages tab, as these settings are now managed via the AppShell (gear icon).

- Removed privacy section HTML from `components/profile-modal.html`.
- Updated `js/ui/profileModalController.js` to remove legacy DOM references and event listeners.
- Preserved `handleReadReceiptsToggle` and `handleTypingIndicatorsToggle` methods for AppShell integration.
- Updated `syncDmPrivacySettingsUi` to be a no-op to prevent errors in existing call sites.

verify_profile.py

@@ -0,0 +1,53 @@
+
+from playwright.sync_api import sync_playwright
+
+def verify_profile_modal():
+    with sync_playwright() as p:
+        browser = p.chromium.launch(headless=True)
+        context = browser.new_context(viewport={'width': 1280, 'height': 720})
+        page = context.new_page()
+
+        # Navigate to the app
+        page.goto("http://localhost:8000")
+
+        # Wait for the page to load
+        page.wait_for_load_state("networkidle")
+
+        # Make the profile modal visible
+        page.evaluate("""() => {
+            const modal = document.getElementById('profileModal');
+            if (modal) {
+                modal.classList.remove('hidden');
+                modal.setAttribute('aria-hidden', 'false');
+            }
+        }""")
+
+        # Force the Messages pane to be visible
+        page.evaluate("""() => {
+            const pane = document.getElementById('profilePaneMessages');
+            if (pane) {
+                pane.classList.remove('hidden');
+                pane.removeAttribute('hidden');
+                // Ensure other panes are hidden if needed, but not strictly necessary for content check
+            }
+        }""")
+
+        # Wait for the pane to become active/visible
+        page.wait_for_selector("#profilePaneMessages:not(.hidden)")
+
+        # Take a screenshot
+        page.screenshot(path="verification_profile_messages.png")
+
+        content = page.content()
+        if "Direct message privacy" in content:
+            print("FAILURE: 'Direct message privacy' text found in the page source.")
+        else:
+            print("SUCCESS: 'Direct message privacy' text NOT found.")
+
+        if "Read receipts" in content and "Direct message privacy" in content:
+             print("FAILURE: 'Read receipts' text found.")
+
+        browser.close()
+
+if __name__ == "__main__":
+    verify_profile_modal()