* feat(terminal): add flag-gated render-desync sentinel for WebGL panes
Detects the buffer-clean/render-stale glyph garble class in the field: per
visible WebGL pane, compare the cells the xterm buffer says hold glyphs
against the ink actually present on the canvas, sampled in the same task as
a forced synchronous redraw so a divergence proves the render model/atlas is
wrong rather than a missed present. A trip requires the same screen cells to
stay divergent across three samples (real desync is pinned; scroll lag moves),
then records a webgl-render-desync breadcrumb, stashes evidence (canvas PNG +
buffer text) for bug reports, and runs the same shared-atlas recovery a tab
reveal performs, so a stuck-garbled pane self-heals within seconds.
Off by default; arm on any build via
localStorage.setItem('orca:render-desync-sentinel', '1') and reload.
* fix(terminal): invalidate glyph cache on atlas replacement
Reproduce the WebGL atlas identity mismatch with two live terminals and force cached geometry to rebuild whenever a different shared atlas is attached. Persist flag-gated render-desync evidence and retain the investigation tooling used to validate the field signature.
* fix(terminal): harden render desync diagnostics
* docs(reliability): clarify Linux WebGL evidence gap
7c0b84f2b6