Fix critical bugs and polish NiceGUI Explorer UI to production grade

- Replace ui.link(on_click=...) crash with ui.button().props("flat dense no-caps")
- Fix broken pagination: use .set_enabled() instead of invalid .props("flat 'disable'")
- Eliminate modal memory leak: reuse singleton ui.dialog() instances
- Add loading spinners during data fetches
- Add proper empty-state cards with icon + message + hint
- Replace hard-coded max-width pixels with Tailwind truncate class
- Wrap all grids in max-w-7xl mx-auto responsive container
- Guard all service calls with try/except and ui.notify() error toasts
- Use opacity classes instead of text-gray-* for dark mode compatibility
- Add page title and favicon to /ui page
- Show fallback badge when stats fail instead of silent swallow
- Move tab imports to module level
- MCP console: disable Run button during execution, show spinner
- MCP console: use ui.code() for JSON output with syntax highlighting
- MCP console: deferred scroll with ui.timer(0.1) after render
- Flow view: professional centered card placeholder

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: aksOps

src/osscodeiq/server/ui/__init__.py

@@ -6,6 +6,9 @@
 
 from nicegui import ui
 
+from osscodeiq.server.ui.explorer import create_explorer_page
+from osscodeiq.server.ui.flow_view import create_flow_page
+from osscodeiq.server.ui.mcp_console import create_mcp_console
 from osscodeiq.server.ui.theme import BRAND_COLOR
 
 if TYPE_CHECKING:
@@ -15,7 +18,7 @@
 def setup_ui(service: CodeIQService) -> None:
     """Register NiceGUI pages on the existing FastAPI app."""
 
-    @ui.page("/ui")
+    @ui.page("/ui", title="OSSCodeIQ Explorer", favicon="hub")
     def index():
         dark = ui.dark_mode(value=None)
 
@@ -26,26 +29,40 @@ def index():
             with ui.row().classes("items-center gap-2"):
                 try:
                     stats = service.get_stats()
-                    ui.badge(f"{stats.get('total_nodes', 0):,} nodes").props("color=primary outline")
-                    ui.badge(f"{stats.get('total_edges', 0):,} edges").props("color=positive outline")
-                except Exception:
-                    pass
-                ui.button(icon="light_mode", on_click=lambda: dark.set_value(False)).props("flat dense round").tooltip("Light theme")
-                ui.button(icon="dark_mode", on_click=lambda: dark.set_value(True)).props("flat dense round").tooltip("Dark theme")
-                ui.button(icon="contrast", on_click=lambda: dark.set_value(None)).props("flat dense round").tooltip("System theme")
+                    ui.badge(
+                        f"{stats.get('total_nodes', 0):,} nodes"
+                    ).props("color=primary outline")
+                    ui.badge(
+                        f"{stats.get('total_edges', 0):,} edges"
+                    ).props("color=positive outline")
+                except Exception:  # noqa: BLE001
+                    ui.badge("stats unavailable").props(
+                        "color=warning outline"
+                    )
+                ui.button(
+                    icon="light_mode",
+                    on_click=lambda: dark.set_value(False),
+                ).props("flat dense round").tooltip("Light theme")
+                ui.button(
+                    icon="dark_mode",
+                    on_click=lambda: dark.set_value(True),
+                ).props("flat dense round").tooltip("Dark theme")
+                ui.button(
+                    icon="contrast",
+                    on_click=lambda: dark.set_value(None),
+                ).props("flat dense round").tooltip("System theme")
 
         with ui.tabs().classes("w-full") as tabs:
             explorer_tab = ui.tab("Explorer", icon="explore")
             flow_tab = ui.tab("Flow", icon="account_tree")
             console_tab = ui.tab("MCP Console", icon="terminal")
 
-        with ui.tab_panels(tabs, value=explorer_tab).classes("w-full flex-grow"):
+        with ui.tab_panels(tabs, value=explorer_tab).classes(
+            "w-full flex-grow"
+        ):
             with ui.tab_panel(explorer_tab):
-                from osscodeiq.server.ui.explorer import create_explorer_page
                 create_explorer_page(service)
             with ui.tab_panel(flow_tab):
-                from osscodeiq.server.ui.flow_view import create_flow_page
                 create_flow_page(service)
             with ui.tab_panel(console_tab):
-                from osscodeiq.server.ui.mcp_console import create_mcp_console
                 create_mcp_console(service)