feat: add batch upload, CLI, and exception hierarchy

- Add RbxError base class with AuthError, RateLimitError, UploadError,
  and AssetNotFoundError subclasses
- Add BatchUploadItem and BatchResult dataclasses
- Add batch_upload method with semaphore-limited concurrency (2 at a time)
- Add configurable max_attempts and poll_interval to upload_clothing_image
- Add CLI with upload and onsale commands (rbx-upload[cli] extra)
- Improve auth error handling across all client methods
- Bump version to 0.2.0

src/rbx_upload/cli.py

@@ -0,0 +1,103 @@
+import asyncio
+import os
+import sys
+
+try:
+    import click
+except ImportError:
+    print(
+        "CLI dependencies are not installed. Run: pip install rbx-upload[cli]",
+        file=sys.stderr,
+    )
+    sys.exit(1)
+
+from .client import RobloxClient
+from .models import RbxAssetType
+
+
+def _get_roblosecurity() -> str:
+    token = os.environ.get("ROBLOSECURITY")
+    if not token:
+        raise click.ClickException(
+            "ROBLOSECURITY environment variable is not set."
+        )
+    return token
+
+
+@click.group()
+def cli():
+    """rbx-upload — Roblox asset upload tool."""
+    pass
+
+
+@cli.command()
+@click.argument("image", type=click.Path(exists=True, readable=True))
+@click.option("--name", "-n", required=True, help="Asset display name.")
+@click.option("--description", "-d", default="", show_default=True, help="Asset description.")
+@click.option(
+    "--type", "-t", "asset_type",
+    type=click.Choice(["shirt", "pants"], case_sensitive=False),
+    default="shirt",
+    show_default=True,
+    help="Asset type.",
+)
+@click.option("--group", "-g", "group_id", required=True, type=int, help="Group ID to upload to.")
+@click.option("--publisher", "-p", "publisher_user_id", required=True, type=int, help="Publisher user ID.")
+@click.option("--max-attempts", default=10, show_default=True, help="Max polling attempts.")
+@click.option("--poll-interval", default=1.0, show_default=True, help="Seconds between polls.")
+def upload(image, name, description, asset_type, group_id, publisher_user_id, max_attempts, poll_interval):
+    """Upload a clothing image to Roblox."""
+    roblosecurity = _get_roblosecurity()
+    asset_type_enum = RbxAssetType.SHIRT if asset_type == "shirt" else RbxAssetType.PANTS
+
+    with open(image, "rb") as f:
+        image_bytes = f.read()
+
+    async def _run():
+        async with RobloxClient(roblosecurity, publisher_user_id) as client:
+            result = await client.upload_clothing_image(
+                image=image_bytes,
+                name=name,
+                description=description,
+                asset_type=asset_type_enum,
+                group_id=group_id,
+                max_attempts=max_attempts,
+                poll_interval=poll_interval,
+            )
+        return result
+
+    result = asyncio.run(_run())
+    asset_id = result.get("asset_id")
+    if asset_id:
+        click.echo(f"Uploaded successfully. Asset ID: {asset_id}")
+    else:
+        click.echo(f"Upload result: {result}")
+
+
+@cli.command()
+@click.argument("asset_id", type=int)
+@click.option("--name", "-n", required=True, help="Asset display name.")
+@click.option("--description", "-d", default="", show_default=True, help="Asset description.")
+@click.option("--group", "-g", "group_id", required=True, type=int, help="Group ID.")
+@click.option("--publisher", "-p", "publisher_user_id", required=True, type=int, help="Publisher user ID.")
+@click.option("--price", default=5, show_default=True, help="Price in Robux.")
+def onsale(asset_id, name, description, group_id, publisher_user_id, price):
+    """Put an asset on sale."""
+    roblosecurity = _get_roblosecurity()
+
+    async def _run():
+        async with RobloxClient(roblosecurity, publisher_user_id) as client:
+            return await client.onsale_asset(
+                asset_id=asset_id,
+                name=name,
+                description=description,
+                group_id=group_id,
+                price=price,
+            )
+
+    asyncio.run(_run())
+    click.echo(f"Asset {asset_id} put on sale for {price} Robux.")
+
+
+def main():
+    cli()