fix(inventory): make wheel scrolling stop when the user does

[naxty]

Summary

Wheel-scrolling formae inventory resources kept moving long after the wheel stopped. Three causes, all on the per-event path:

• Redundant pipeline work per key. Every navigation key re-ran filter → sort → truncate → per-cell styling over the capped row set, and the render path re-ran the filter and sort twice more per frame — for a result a cursor move cannot change. Navigation no longer re-syncs; the view path counts filtered rows without sorting them.
• One notch was several events. Without mouse tracking, a terminal in the alternate screen translates a wheel notch into several arrow keys, so each notch cost several full frames. The inventory TUI now enables tracking and sizes the step itself. Other TUIs are unchanged; FORMAE_TUI_NO_MOUSE=1 opts out for anyone who would rather keep click-drag text selection (with tracking on, selection needs shift held).
• A frame per queued event. Bubbletea renders after every message, so a fast flick still queued more frames than the renderer could retire and the surplus drained after the user stopped. Wheel travel now accumulates and a settle tick applies the total in one move and one repaint; mid-burst frames reuse the last paint.

Per queued notch: 8.45 ms → 0.011 ms, plus one 2.2 ms settle per burst (1000 resources, benchmarks included).

Two display bugs surfaced while fixing the render path — both pre-existing, both made trivial to hit by wheel scrolling:

• Resizing the table rebuilt the wrapped table's rows, which reset its scroll offset while keeping the cursor. Since the render path resizes on every frame, the selected row left the screen after roughly one screenful of travel — no row highlighted, and Enter opened detail for a row the user could not see. Same-size resizes are now a no-op, and only width changes reproject (height cannot change which columns fit).
• Per-cell styling was applied by absolute row index onto a window of rendered lines, so once scrolled it targeted the wrong rows and silently vanished. It now aligns to the rendered window.

Covered by new tests for wheel coalescing, frame reuse, scroll-follow, and the filtered-count equality that the split view path relies on. Golden renders are unchanged.