fix(cli): restore hyperframes capture <url>; move video download to --video flag

PR #1447 added `capture video` as a citty subCommand. citty's runCommand
(node_modules/.bun/citty@0.2.2/.../dist/index.mjs:209-227) treats any non-flag
positional as a subcommand-name attempt and throws E_UNKNOWN_COMMAND when it
doesn't match — there's no fallback to the parent's positional args, so
`hyperframes capture https://vercel.com` died with "Unknown command https://vercel.com".

Per James's suggestion, surface video-download as `capture --video <project>`
(a mode flag) instead of a subcommand. Citty has no issue with a positional
URL coexisting with flags. `video.ts` now exports `runVideoMode()` instead of
a `defineCommand` default export.

- `hyperframes capture <url>` works again
- `hyperframes capture --video <project> --index N` downloads video
- `hyperframes capture --video <project> --list` lists manifest
- `hyperframes capture --video <project> --video-url <url>` downloads by URL

packages/cli/src/commands/capture.ts

@@ -8,7 +8,11 @@ export const examples: Example[] = [
   ["JSON output for AI agents", "hyperframes capture https://example.com --json"],
   [
     "Pull a video from the captured manifest by index",
-    "hyperframes capture video ./linear-video --index 0",
+    "hyperframes capture --video ./linear-video --index 0",
+  ],
+  [
+    "List videos referenced in the captured manifest",
+    "hyperframes capture --video ./linear-video --list",
   ],
 ];
 
@@ -17,14 +21,11 @@ export default defineCommand({
     name: "capture",
     description: "Capture a website as editable HyperFrames components",
   },
-  subCommands: {
-    video: () => import("./capture/video.js").then((m) => m.default),
-  },
   args: {
     url: {
       type: "positional",
-      description: "Website URL to capture",
-      required: true,
+      description: "Website URL to capture (omit when using --video)",
+      required: false,
     },
     output: {
       type: "string",
@@ -49,12 +50,44 @@ export default defineCommand({
       description: "Output JSON (for AI agents / programmatic use)",
       default: false,
     },
+    video: {
+      type: "string",
+      description:
+        "Switch to video-download mode: path to a captured project directory whose video-manifest.json should be read. Pair with --index, --video-url, or --list.",
+    },
+    index: {
+      type: "string",
+      description: "(--video mode) Manifest entry index to download (0-based)",
+    },
+    "video-url": {
+      type: "string",
+      description: "(--video mode) Exact video URL to download (must match a manifest entry)",
+    },
+    list: {
+      type: "boolean",
+      description: "(--video mode) List manifest entries and exit",
+      default: false,
+    },
   },
   async run({ args }) {
-    const url = args.url as string;
+    if (args.video) {
+      const { runVideoMode } = await import("./capture/video.js");
+      await runVideoMode({
+        project: args.video as string,
+        index: (args.index as string | undefined) ?? null,
+        url: (args["video-url"] as string | undefined) ?? null,
+        list: args.list as boolean,
+      });
+      return;
+    }
 
-    // citty fires parent's run AFTER routing to a subcommand; skip when args.url is a subcommand name.
-    if (url === "video") return;
+    const url = args.url as string | undefined;
+    if (!url) {
+      console.error(
+        "Missing URL. Pass a website URL, or use --video <project> for video download.",
+      );
+      process.exit(1);
+    }
 
     try {
       new URL(url);