fix(security): harden privileged renderer boundaries

Reject renderer-owned queue internals before persistence and bind privileged handlers to trusted renderer events. Extend cutter session capabilities without weakening owner, purpose, path identity, or expiry checks. Migrate release harness contracts to opaque capabilities and add an invisible Node gate.

src/main/domain/renderer-queue-input.test.ts

@@ -0,0 +1,90 @@
+import { existsSync, mkdtempSync, rmSync, writeFileSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+import { describe, expect, it } from 'vitest';
+import { createRendererQueueItem, getMergeGroupCleanupPaths, normalizeRendererQueueInput } from './renderer-queue-input';
+
+describe('renderer queue input', () => {
+    it('keeps only validated renderer-owned queue fields', () => {
+        const directory = mkdtempSync(join(tmpdir(), 'tvm-renderer-queue-'));
+        const victim = join(directory, 'important.txt');
+        writeFileSync(victim, 'keep');
+        const normalized = normalizeRendererQueueInput({
+            id: 'forged-id',
+            status: 'completed',
+            progress: 100,
+            url: 'https://www.twitch.tv/videos/123456789',
+            title: 'Fixture title',
+            date: '2026-08-11T20:00:00.000Z',
+            streamer: 'fixture_streamer',
+            duration_str: '1h2m3s',
+            outputFiles: ['C:\\Users\\victim\\important.txt'],
+            mergeGroup: {
+                items: [],
+                mergePhase: 'done',
+                currentItemIndex: 0,
+                downloadedFiles: { 0: 'C:\\Users\\victim\\important.txt' },
+                mergedFile: 'C:\\Users\\victim\\another-important.txt',
+            },
+            isLive: true,
+            recordingHealth: 'ok',
+            last_error: 'forged',
+        });
+
+        expect(normalized).toEqual({
+            url: 'https://www.twitch.tv/videos/123456789',
+            title: 'Fixture title',
+            date: '2026-08-11T20:00:00.000Z',
+            streamer: 'fixture_streamer',
+            duration_str: '1h2m3s',
+        });
+        expect(JSON.stringify(normalized)).not.toContain('important.txt');
+        const queueItem = createRendererQueueItem({
+            ...normalized,
+            mergeGroup: { downloadedFiles: { 0: victim }, mergedFile: victim },
+        }, 'main-owned-id');
+        for (const cleanupPath of getMergeGroupCleanupPaths(queueItem ?? undefined)) rmSync(cleanupPath, { force: true });
+        expect(existsSync(victim)).toBe(true);
+        rmSync(directory, { recursive: true, force: true });
+    });
+
+    it('normalizes a valid custom clip without accepting extra fields', () => {
+        const normalized = normalizeRendererQueueInput({
+            url: 'https://www.twitch.tv/videos/123456789',
+            title: 'Fixture title',
+            date: '2026-08-11T20:00:00.000Z',
+            streamer: 'fixture_streamer',
+            duration_str: '1h2m3s',
+            customClip: {
+                startSec: 12.5,
+                durationSec: 30,
+                startPart: 1,
+                filenameFormat: 'template',
+                filenameTemplate: '{date}_{title}',
+                mergedFile: 'C:\\forged.mp4',
+            },
+        });
+
+        expect(normalized?.customClip).toEqual({
+            startSec: 12.5,
+            durationSec: 30,
+            startPart: 1,
+            filenameFormat: 'template',
+            filenameTemplate: '{date}_{title}',
+        });
+    });
+
+    it('rejects malformed queue requests before they can enter persistent state', () => {
+        expect(normalizeRendererQueueInput(null)).toBeNull();
+        expect(normalizeRendererQueueInput({ url: 'file:///C:/victim.txt', title: 'x', date: 'x', streamer: 'x', duration_str: '1s' })).toBeNull();
+        expect(normalizeRendererQueueInput({ url: 'https://www.twitch.tv/videos/1', title: '', date: 'x', streamer: 'x', duration_str: '1s' })).toBeNull();
+        expect(normalizeRendererQueueInput({
+            url: 'https://www.twitch.tv/videos/1',
+            title: 'x',
+            date: 'x',
+            streamer: 'x',
+            duration_str: '1s',
+            customClip: { startSec: -1, durationSec: 10, startPart: 1, filenameFormat: 'simple' },
+        })).toBeNull();
+    });
+});