D343 M2: GE-styled options panel on file select; D344 docs

The file-select Options label opens a panel drawn in the same hook:
sections as tabs, rows from the F10 overlay's table via an exported row
API, the game's crosshair as pointer (input.c passes the stick, hands the
buttons to the panel). Quit to desktop now goes through videoRequestQuit.
Also repairs two escaped-newline typos in the D343 docs.

docs/porting-notes.md

@@ -1280,6 +1280,12 @@ GE on N64 renders gameplay at ~20–30 fps, so `g_ClockTimer` (= `speedgraphfram
 
 ## E. Process / method notes
 
+- **Never `exit()` while another thread may be inside the GL driver (D344).**
+  The GL context lives on the render (scheduler) thread; quit events arrive on
+  other threads. Request the quit (`videoRequestQuit`), let the render thread
+  `glFinish` + unbind at a frame boundary and park, then exit from the host.
+  An unclean GL teardown bugchecked the maintainer's PC (0x119, HAGS on).
+  Harness runs should end with `GE_QUITFRAME=<n>`, not a `timeout` kill.
 - **Headless front-end scripts: turn the mouse off (D343).** In menus the
   pointer follows the real OS mouse (WI-2 absolute tracking), so the desktop
   mouse moves the in-game cursor mid-`GE_INPUTSCRIPT`. Put
@@ -1287,8 +1293,7 @@ GE on N64 renders gameplay at ~20–30 fps, so `g_ClockTimer` (= `speedgraphfram
   about one per rendered frame on the file select screen; calibrate with a
   log, not by assumption.
 - **`textMeasure` height is 0 without a trailing newline (D343).** It only
-  counts completed lines. Measure `"text
-"` when you need a height (front.c's
+  counts completed lines. Measure `"text\n"` when you need a height (front.c's
   folder text does this); the width is unaffected.
 - **Periodic audio glitches: measure the host audio device before touching
   the pipeline (D322).** A clock-regular overflow/garble pattern (~5 min period,