docs(agent): #95 both Ghostty fails are Acer pre/post HM, XPS is fine

Bernardo: XPS starts Ghostty. Aspire only fails — first attempt before
home built (OpenGLOutdated), second after home built (quiet GDK_DISABLE
exit). Kitty was the manual working shell used to run both.

agent/BACKLOG.md

@@ -144,12 +144,17 @@ template source. Pass = Chromium launches after installation and HTTP/HTTPS
 mime defaults resolve to `chromium-browser.desktop` (and the intended live-ISO
 browser posture is explicit).
 
-### 95. Live ISO/install: Ghostty does not open — **two distinct failures**
+### 95. Live ISO/install: Ghostty does not open on Acer (old GL + two log shapes)
 
-Two photos, two machines, **two different Ghostty death modes**. Do not
-collapse them into one "old GPU" fix; a fix for (A) can leave (B) broken.
+**Machine:** Acer Aspire M5-481T only. **Dell XPS 9350 starts Ghostty fine**
+(Bernardo clarified 2026-07-15 — do not treat XPS as a Ghostty failure).
 
-**A — Acer Aspire M5-481T: OpenGL too old (explicit)**
+On the Acer, Bernardo installed **kitty** by hand (worked) and launched
+Ghostty from that shell twice — **same box, two lifecycle points, two log
+shapes**:
+
+**1 — Before Home Manager was properly built** (partial first boot after
+#123 bake failure). Explicit GPU floor:
 
 ```
 info(opengl): loaded OpenGL 4.2
@@ -160,11 +165,7 @@ warning(gtk_ghostty_surface): surface failed to initialize
   err=error.SurfaceError
 ```
 
-Ghostty 1.3.1 starts, loads config, hits the GPU floor, prints the reason,
-returns to the shell (~2s). Anything ≤ GL 4.2 (Ivy Bridge era) is dead for
-the default terminal.
-
-**B — Dell XPS 9350 (photo without Acer bezel): silent exit after GDK_DISABLE**
+**2 — After home was built** (full HM generation). Silent-ish exit:
 
 ```
 warning(gtk_ghostty_application): setting GDK_DEBUG=
@@ -172,29 +173,30 @@ warning(gtk_ghostty_application): setting GDK_DISABLE=gles-api,vulkan
 ~ 9s )
 ```
 
-Same Ghostty 1.3.1 / GTK path / config read — but **no** `info(opengl):`
-line, **no** OpenGLOutdated, **no** SurfaceError. Process ends after ~9s
-and leaves only the two `GDK_*` warnings. XPS Skylake iGPU is not a GL-4.2
-floor machine; this is a different surface/backend failure (forced desktop
-OpenGL after disabling GLES+Vulkan, Wayland/EGL context, incomplete first
-session after #123, …). Capture a second run with `GDK_DEBUG` / Ghostty
-`-e` verbosity or `WAYLAND_DEBUG=1` before guessing the patch.
+No `info(opengl):` line, no `OpenGLOutdated`, no `SurfaceError` — process
+ends after ~9s with only the two `GDK_*` warnings. Same Ghostty 1.3.1, same
+machine; the difference is **session/config state after HM**, not a second
+GPU. Likely still the GL 4.2 floor (or the same surface path) with different
+verbosity once the full Ghostty/GTK/Stylix config is in place — confirm
+before inventing a second root cause. Re-run post-HM with extra logging
+(`GDK_DEBUG`, Ghostty verbosity, `WAYLAND_DEBUG=1`) if the quiet path is
+still opaque.
 
-**Shared product impact:** default terminal is Ghostty (`nomarchy.terminal`),
-so SUPER+Return and the launcher entry are dead when either mode hits.
-Bernardo worked around on the Acer by adding `kitty` to `home.packages`.
+**Product impact:** default terminal is Ghostty (`nomarchy.terminal`), so on
+this class of GPU SUPER+Return and the launcher entry are dead. Kitty as a
+manual workaround proved the session/Wayland path is fine.
 
-**Fix direction (likely two slices):**
-1. **(A)** soft-fallback or alternate default when GL < 4.3 (probe, or
-   ship a second terminal and bind/fallback).
-2. **(B)** reproduce on XPS-class hardware or QEMU with a capable GL stack;
-   fix the silent path (must never exit without a user-visible error or a
-   working window). May interact with #123 if the first session is half-baked.
+**Fix direction:** treat the **GL ≥ 4.3 requirement** as the primary Acer
+blocker (soft-fallback, alternate default terminal when GL < 4.3, or
+installer/hardware probe that swaps the default). Do not leave SUPER+Return
+bound to a terminal that cannot map a surface. Optionally make the post-HM
+failure mode print the OpenGL reason again so the quiet log is not a
+support trap.
 
-**Pass:** SUPER+Return opens a usable terminal on **both** the Acer (A) and
-the XPS (B); modern-GL machines still get themed Ghostty by default; a
-regression that only fixes A or only B is not done. V2 may cover (A) via
-softGL version pinning; (B) needs the XPS or a faithful GL/Wayland guest.
+**Pass:** on the Acer (or a GL 4.2 / softGL stand-in), SUPER+Return opens a
+usable terminal without hand-editing `home.packages`; modern-GL machines
+(including the XPS) still get themed Ghostty by default. V2 softGL may cover
+the floor; V3 on the Acer is the real check.
 
 ### 98. Boreal: button text renders black and is difficult to read