feat: tips shown during thinking spinner (like Claude Code bootstrap tips)

[VforVitorio]

Context

Claude Code shows a rotating tip below the spinner while loading:

* Bootstrapping…
  └ Tip: /mobile to use Claude Code from the Claude app on your phone

This reduces perceived wait time and teaches users features passively.

Proposed behaviour

While the thinking spinner runs, show a random tip below it:

⠋ thinking…  42 tok
  tip: use /verbose to see which tools the model is calling

Tips rotate every ~3 seconds or just show one per turn (simpler).

Tip content (initial set)

• "use /verbose to see tool calls in real time"
• "Tab cycles ask → auto → strict mode"
• "/clear resets the conversation history"
• "drop a LMCODE.md in your project root to give the model context"
• "use /mode strict for pure chat with no file access"
• "try /model to see which model is loaded"
• "run lmcode --help for all CLI flags"

Implementation

• _TIPS: list[str] constant in core.py or status.py
• random.choice(_TIPS) each turn
• Rendered as a second line inside the Live context

[VforVitorio]

Implemented in feat/ui-status-bar. Rotating tips are shown beneath the thinking spinner (same pattern as Claude Code bootstrap tips). Tips cycle on a timer and are toggled via /tips.