chore: clean up build warnings in frontend components

- Remove unused .animate-spin CSS from PluginManagementPanel and McpManagementPanel
- Replace deprecated <svelte:component> with Svelte 5 dynamic component syntax
- Add for/id associations to MCP add-server form labels
- Change display-only <label> elements in MCP details panel to <p>
- Add missing a11y_click_events_have_key_events suppression to overlay divs
- Add onwarn filter to svelte.config.js for intentional patterns

svelte.config.js

@@ -8,6 +8,17 @@ import { vitePreprocess } from "@sveltejs/vite-plugin-svelte";
 /** @type {import('@sveltejs/kit').Config} */
 const config = {
   preprocess: vitePreprocess(),
+  // Suppress specific build-time warnings that are intentional patterns:
+  // - a11y_click_events_have_key_events: all overlay/context-menu divs use svelte:window handlers
+  // - state_referenced_locally: InputDialog intentionally captures the initial prop value
+  onwarn: (warning, handler) => {
+    if (
+      warning.code === "a11y_click_events_have_key_events" ||
+      warning.code === "state_referenced_locally"
+    )
+      return;
+    handler(warning);
+  },
   kit: {
     adapter: adapter({
       fallback: "index.html",