feat(alerts): always-visible dismiss/ack actions + Dismiss all (service, endpoint, UI)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/app/api/v1/alerts/dismiss-all/route.ts

@@ -0,0 +1,23 @@
+import { NextResponse } from 'next/server';
+import { z } from 'zod';
+
+import { withAuth } from '@/lib/api/helpers';
+import { parseBody } from '@/lib/api/route-helpers';
+import { errorResponse } from '@/lib/errors';
+import { ALERT_RULES } from '@/lib/db/schema/insights';
+import { dismissAllForPort } from '@/lib/services/alerts.service';
+
+const bodySchema = z.object({
+  ruleId: z.enum(ALERT_RULES).optional(),
+  severity: z.enum(['info', 'warning', 'critical']).optional(),
+});
+
+export const POST = withAuth(async (req, ctx) => {
+  try {
+    const { ruleId, severity } = await parseBody(req, bodySchema);
+    const dismissed = await dismissAllForPort(ctx.portId, ctx.userId, { ruleId, severity });
+    return NextResponse.json({ data: { dismissed } });
+  } catch (error) {
+    return errorResponse(error);
+  }
+});