v1.4.0

• Added a new Why tabs are not suspending diagnostics panel in Options with manual refresh.
• Added local-only per-tab suspension diagnostics showing tab title, full URL, and deterministic suspend reason.
• Added reason summary counts across open tabs, including eligible tabs for transparency.
• Added bounded diagnostics rendering (max 200 tab rows) to keep Options responsive on large tab sets.
• Added runtime diagnostics endpoint and regression coverage for diagnostics success, failure, empty, and truncated states.