Add discoverability hints for row context-menu actions

[djdcks12]

Description

Several core 0.8 workflows are now exposed through right-click context menus:

• Output tree rows: Add Watch, Copy Path, Insert into Code, Pin as, Inspect This.
• Object Browser rows: Inspect, Set as _, Pin as, Patch Method, Insert into Code.
• Watch rows: Insert into Code.

These actions are useful, but new users may not discover them because there is no visible hint that rows are interactive beyond double-click behavior.

Why

The main user loop is now:

1. Inspect something in Output or Object Browser.
2. Add important paths to Watch.
3. Insert useful access snippets back into Code.
4. Pin objects that should be referenced repeatedly.
5. Patch a method when runtime behavior needs temporary override.

Most of that loop depends on row context menus. A small hint can make the tool feel much easier to learn.

Suggested Fix

Add a subtle discoverability hint in one or more low-noise places:

• Ready/empty Output message.
• Object Browser empty state.
• Watch empty state.
• README quick-start section.

Example copy:

Tip: right-click Output, Object Browser, or Watch rows for Watch, Pin, Insert, and Patch actions.

Acceptance Criteria

• At least one in-app hint mentions right-click row actions.
• README quick-start or workflow section mentions row context menus.
• The hint does not add visual clutter to normal usage.
• No behavior changes are required.