fix: make depth meter meaningful with dynamic rlm_query call counter

[ratacat]

Problem

The depth meter showed ∞ depth 0/3 at all times during interactive use. Since children run headless (pi -p), the user never sees depth > 0. The status bar was effectively a static label.

Fix

1. Read RLM_DEPTH dynamically — replaced module-level constants with getDepth()/getMaxDepth() that re-read process.env on every update
2. Track rlm_query calls — hooked into tool_result to detect bash commands containing rlm_query and increment a counter
3. Show call counter in status — the bar now shows ypi ∞ d0/3 · 3 calls so the human gets visual feedback that recursion is happening
4. Refresh on turn_end — status bar updates after every agent turn (previously only on session start/switch)
5. Depth in terminal title — ypi d0 instead of just ypi

Behavior

ypi  ∞ d0/3              ← fresh session
ypi  ∞ d0/3 · 1 call     ← after first rlm_query returns
ypi  ∞ d0/3 · 3 calls    ← after three recursive calls

If ypi is ever run at depth > 0 with a visible TUI, the depth number updates accordingly — but the main interaction is the call counter ticking up as rlm_query calls complete.