feat(mcp): add Antigravity, fix Gemini http/sse shape, report unsupported CLIs

Formats verified against real agy/gemini/codex mcp add output.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/web/public/settings-ui.js

@@ -1140,7 +1140,10 @@ Object.assign(CodemanApp.prototype, {
     const conflicts = data.conflicts.length
       ? `<p>Defined differently across CLIs, left unchanged: ${data.conflicts.map(escapeHtml).join(', ')}</p>`
       : '';
-    show(`<ul>${rows.join('')}</ul>${conflicts}`);
+    const unsupported = data.unsupported?.length
+      ? `<p>No MCP config support for: ${data.unsupported.map(escapeHtml).join(', ')}</p>`
+      : '';
+    show(`<ul>${rows.join('')}</ul>${conflicts}${unsupported}`);
   },
 
   _setUpdateResult(html) {

src/web/routes/mcp-sync-routes.ts

@@ -30,12 +30,19 @@ function gate(req: FastifyRequest): ApiResponse<never> | null {
   return null;
 }
 
+/** Enabled agent CLIs with no known MCP config file (sync cannot touch them). */
+export function mcpUnsupportedLabels(): string[] {
+  return enabledClis()
+    .filter((e) => e.kind === 'agent' && !e.capabilities.mcpConfig)
+    .map((e) => e.label);
+}
+
 export function registerMcpSyncRoutes(app: FastifyInstance): void {
   const run = async (req: FastifyRequest, apply: boolean): Promise<ApiResponse<McpSyncResult>> => {
     const denied = gate(req);
     if (denied) return denied;
     try {
-      return { success: true, data: await syncMcpServers(mcpSyncTargets(), { apply }) };
+      return { success: true, data: await syncMcpServers(mcpSyncTargets(), { apply }, mcpUnsupportedLabels()) };
     } catch (err) {
       return createErrorResponse(ApiErrorCode.OPERATION_FAILED, getErrorMessage(err));
     }