feat(ui): M4 — agent activity, knowledge search, audit, correlation grouping

Add three new pages completing the control-room web UI:
- Agent activity: polls /agent-activity every 5s, filterable by type/agent
- Knowledge search: FTS over /knowledge/search with snippet + entity links
- Audit trail: browseable audit log with actor/action/entity filters

Enhanced live events page with correlation-id clustering (Groups toggle).
Added fetchAgentActivity/searchKnowledge/fetchAudit to the API client.
11 nav items now cover all planned control-room views.

web/components.json

@@ -0,0 +1,17 @@
+{
+	"$schema": "https://shadcn-svelte.com/schema.json",
+	"style": "vega",
+	"tailwind": {
+		"css": "src/app.css",
+		"baseColor": "zinc"
+	},
+	"aliases": {
+		"components": "$lib/components",
+		"utils": "$lib/utils",
+		"ui": "$lib/components/ui",
+		"hooks": "$lib/hooks",
+		"lib": "$lib"
+	},
+	"typescript": true,
+	"registry": "https://shadcn-svelte.com/registry"
+}