Polish UI: enhance dialogs, command palette, and page layouts

Expand NewIssueDialog with richer form fields. Add NewProjectDialog.
Enhance CommandPalette with more actions and search. Improve
CompanySwitcher, EmptyState, and IssueProperties. Flesh out Activity,
Companies, Dashboard, and Inbox pages with real content and layouts.
Refine sidebar, routing, and dialog context. CSS tweaks for dark theme.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

ui/src/pages/Agents.tsx

@@ -1,4 +1,4 @@
-import { useState, useCallback, useEffect } from "react";
+import { useState, useEffect } from "react";
 import { useNavigate } from "react-router-dom";
 import { useAgents } from "../hooks/useAgents";
 import { useCompany } from "../context/CompanyContext";
@@ -21,17 +21,6 @@ export function Agents() {
     setBreadcrumbs([{ label: "Agents" }]);
   }, [setBreadcrumbs]);
 
-  async function invoke(e: React.MouseEvent, agentId: string) {
-    e.stopPropagation();
-    setActionError(null);
-    try {
-      await agentsApi.invoke(agentId);
-      reload();
-    } catch (err) {
-      setActionError(err instanceof Error ? err.message : "Failed to invoke agent");
-    }
-  }
-
   if (!selectedCompanyId) {
     return <EmptyState icon={Bot} message="Select a company to view agents." />;
   }
@@ -45,7 +34,10 @@ export function Agents() {
       {actionError && <p className="text-sm text-destructive">{actionError}</p>}
 
       {agents && agents.length === 0 && (
-        <EmptyState icon={Bot} message="No agents yet." />
+        <EmptyState
+          icon={Bot}
+          message="No agents yet. Agents are created via the API or templates."
+        />
       )}
 
       {agents && agents.length > 0 && (