feat!: harden raw browser control and packaging

- Add safe-by-default policy gates for raw command surfaces: command, script, and serve-http /command.

- Require explicit opt-ins for page reads, browser control, and high-risk commands such as dom.eval, storage.*, and screenshots.

- Remove all cookies support from CLI, SDK, extension commands, permissions, constants, docs, and tests.

- Add diagnostic, events, watch, workspace, remote, raw command, script, HTTP gateway, tree-view, session import/export, and extension info/capability commands.

- Add Chrome Web Store packaging that strips manifest.key while keeping local packages with a stable native-messaging extension ID.

- Bump browser-cli and extension version to 0.14.1 and cover the new behavior with pytest and extension packaging tests.

BREAKING CHANGE: cookies commands and the b.cookies SDK namespace have been removed; generic raw command execution now blocks non-safe commands unless explicitly allowed.

browser_cli/commands/session.py

@@ -1,3 +1,5 @@
+import json
+from pathlib import Path
 import click
 from browser_cli.commands import client_from_ctx, gentle_mode_option, handle_errors
 from rich.console import Console
@@ -44,6 +46,33 @@ def session_load(name, gentle_mode, discard_background_tabs, lazy, eager_tabs, b
     count = result.get("tabs", 0) if isinstance(result, dict) else 0
     console.print(f"[green]Session '{name}' loaded[/green] ({count} tabs opened)")
 
+@session_group.command("export")
+@click.argument("name", required=False)
+@click.option("-o", "output", type=click.Path(dir_okay=False, path_type=Path), default=None, help="Write JSON to file instead of stdout")
+@handle_errors
+def session_export(name, output):
+    """Export one saved session, or all sessions as JSON."""
+    data = client_from_ctx().session.export(name)
+    text = json.dumps(data, indent=2, sort_keys=True)
+    if output:
+        output.write_text(text + "\n", encoding="utf-8")
+        console.print(f"[green]Exported session data to {output}[/green]")
+    else:
+        click.echo(text)
+
+@session_group.command("import")
+@click.argument("name")
+@click.argument("file", type=click.Path(exists=True, dir_okay=False, path_type=Path))
+@click.option("--overwrite", is_flag=True, help="Replace an existing saved session")
+@handle_errors
+def session_import(name, file, overwrite):
+    """Import a saved session JSON file."""
+    payload = json.loads(file.read_text(encoding="utf-8"))
+    session = payload.get("session", payload) if isinstance(payload, dict) else payload
+    result = client_from_ctx().session.import_(name, session, overwrite=overwrite)
+    count = result.get("tabs", 0) if isinstance(result, dict) else 0
+    console.print(f"[green]Imported session '{name}'[/green] ({count} tabs)")
+
 @session_group.command("diff")
 @click.argument("name_a")
 @click.argument("name_b")