feat: add performance controls for large browser ops

- Add throttled large-operation handling for tab, group, and session commands.
- Introduce performance profiles, audible-tab aware gentle mode, and job progress tracking.
- Support background session restores with status/cancel commands and lazy placeholders.
- Expose new perf and extension CLI groups plus matching Python SDK methods.
- Preserve pinned tabs during session snapshots and debounce auto-save updates.
- Bump browser-cli and extension versions to 0.10.0 and add pytest-cov to dev deps.
- Add coverage for performance controls, background jobs, lazy restores, and tab metadata.

browser_cli/commands/perf.py

@@ -0,0 +1,45 @@
+import click
+from rich.console import Console
+from rich.table import Table
+from browser_cli.commands import _handle
+
+console = Console()
+
+@click.group("perf")
+def perf_group():
+    """Inspect and tune browser-cli performance behavior."""
+
+@perf_group.command("status")
+def perf_status():
+    """Show performance profile, throttle and running jobs."""
+    result = _handle("perf.status") or {}
+    console.print(f"Profile: [bold]{result.get('performanceProfile', 'auto')}[/bold]")
+    console.print(f"Audible tabs: {'yes' if result.get('audible') else 'no'}")
+    throttle = result.get("throttle") or {}
+    console.print(f"Throttle: batch={throttle.get('batchSize')} pause={throttle.get('pauseMs')}ms mode={throttle.get('mode')}")
+
+    jobs = result.get("jobs") or []
+    if not jobs:
+        console.print("[yellow]No running jobs[/yellow]")
+        return
+
+    table = Table(show_header=True, header_style="bold cyan")
+    table.add_column("Job")
+    table.add_column("Command")
+    table.add_column("Status")
+    table.add_column("Progress", justify="right")
+    table.add_column("Phase")
+    for job in jobs:
+        total = job.get("total")
+        current = job.get("current") or 0
+        percent = job.get("percent") or 0
+        progress = f"{current}/{total} ({percent}%)" if total else f"{percent}%"
+        table.add_row(job.get("id", ""), job.get("command", ""), job.get("status", ""), progress, job.get("phase", ""))
+    console.print(table)
+
+@perf_group.command("profile")
+@click.argument("profile", type=click.Choice(["auto", "normal", "gentle", "ultra"]))
+def perf_profile(profile):
+    """Set global performance profile."""
+    result = _handle("perf.set_profile", {"profile": profile}) or {}
+    console.print(f"[green]Performance profile set to {result.get('performanceProfile', profile)}[/green]")