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/src/lib/components/ui/input/input.svelte

@@ -0,0 +1,48 @@
+<script lang="ts">
+	import type { HTMLInputAttributes, HTMLInputTypeAttribute } from "svelte/elements";
+	import { cn, type WithElementRef } from "$lib/utils.js";
+
+	type InputType = Exclude<HTMLInputTypeAttribute, "file">;
+
+	type Props = WithElementRef<
+		Omit<HTMLInputAttributes, "type"> &
+			({ type: "file"; files?: FileList } | { type?: InputType; files?: undefined })
+	>;
+
+	let {
+		ref = $bindable(null),
+		value = $bindable(),
+		type,
+		files = $bindable(),
+		class: className,
+		"data-slot": dataSlot = "input",
+		...restProps
+	}: Props = $props();
+</script>
+
+{#if type === "file"}
+	<input
+		bind:this={ref}
+		data-slot={dataSlot}
+		class={cn(
+			"dark:bg-input/30 border-input focus-visible:border-ring focus-visible:ring-ring/50 aria-invalid:ring-destructive/20 dark:aria-invalid:ring-destructive/40 aria-invalid:border-destructive dark:aria-invalid:border-destructive/50 h-9 rounded-md border bg-transparent px-2.5 py-1 text-base shadow-xs transition-[color,box-shadow] file:h-7 file:text-sm file:font-medium focus-visible:ring-3 aria-invalid:ring-3 md:text-sm file:text-foreground placeholder:text-muted-foreground w-full min-w-0 outline-none file:inline-flex file:border-0 file:bg-transparent disabled:pointer-events-none disabled:cursor-not-allowed disabled:opacity-50",
+			className
+		)}
+		type="file"
+		bind:files
+		bind:value
+		{...restProps}
+	/>
+{:else}
+	<input
+		bind:this={ref}
+		data-slot={dataSlot}
+		class={cn(
+			"dark:bg-input/30 border-input focus-visible:border-ring focus-visible:ring-ring/50 aria-invalid:ring-destructive/20 dark:aria-invalid:ring-destructive/40 aria-invalid:border-destructive dark:aria-invalid:border-destructive/50 h-9 rounded-md border bg-transparent px-2.5 py-1 text-base shadow-xs transition-[color,box-shadow] file:h-7 file:text-sm file:font-medium focus-visible:ring-3 aria-invalid:ring-3 md:text-sm file:text-foreground placeholder:text-muted-foreground w-full min-w-0 outline-none file:inline-flex file:border-0 file:bg-transparent disabled:pointer-events-none disabled:cursor-not-allowed disabled:opacity-50",
+			className
+		)}
+		{type}
+		bind:value
+		{...restProps}
+	/>
+{/if}