Add delete function (single and group)

[sbagg]

Delete Requirements

Delete single cookie

• Button per cookie: “Delete”
• Must attempt expiration with:
  • Path=/
  • Host-only delete
  • Parent-domain delete (computed or overridden)

Delete group

• Button per group: “Delete group”
• Deletes every cookie in the group

After deletion

• Refresh cookie list immediately
• If cookies remain, show warning:

Some cookies could not be removed (domain/path mismatch or HttpOnly).