UNIFY: one exe -- retire the pod/glass/steam compile split

The three build dirs (build\ pod, build-glass\, build-steam\) were compile-
time splits of the same game; the tax was real: a stale steam exe shipped 2
days behind, the felt keymap flipped with the boot flavor, and cockpit
clicks were silently dead in the pod build (the trigger-config incident).

Now everything compiles into the single build\ exe:
- CMakeLists: BT_GLASS/BT_STEAM options removed; the glass TUs (PadRIO,
  bindings, panel, glass windows, plasma) + FE/console + Steam transport
  compile unconditionally; both macros always defined (seam markers).
- Steam: steam_api.lib linked with /DELAYLOAD:steam_api.dll + delayimp --
  the DLL maps only when SteamAPI is first called, and every call site
  gates on BT_STEAM_NET=1 (BTSteamNet_* short-circuit on steamActive), so
  machines without the DLL run everything but Steam sessions.
- CABINET GUARD (btl4main): the miniconsole menu previously claimed any
  zero-arg launch -- unified, that would hijack the pod cabinet's boot
  shape.  The menu now requires BT_PLATFORM=glass (or BT_FE_MENU=1);
  platform parse moved above the fe_menu_mode computation.  A bare boot
  behaves exactly like the old pod build (DEV profile, wait for egg).
- Bats (play_solo/join/join_lan/play_steam) + the btoperator.py template:
  single build\ path + BT_PLATFORM=glass.  mkdist: one exe (+DLL scan
  picks up OpenAL32 + steam_api).  build-glass\/build-steam\/build-glass2\
  (a stale Jul-20 cache) deleted.

Verified matrix on the unified exe:
  bare zero-arg boot == old pod exe (same DEV profile + egg-load path;
    the segfault on a missing egg is pre-existing, baselined vs the zip exe)
  glass + BT_BTNTEST scripted click -> [cfgmap] ENTER/EXIT (trigger config)
  runs with steam_api.dll ABSENT (delay-load proven)
  glass zero-arg -> miniconsole menu
  2-node loopback MP: 145 ticks each, cross-connected
  BT_STEAM_NET=1 without Steam client -> "staying on Winsock", game runs

KB: context/glass-cockpit.md compile-gates section rewritten for the
unified model.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tools/btoperator.py

@@ -786,15 +786,11 @@ class Operator(QMainWindow):
         def guarded(header, sets, run, tail):
             return ("@echo off\n" + header +
                     "cd /d %~dp0\n"
-                    # Prefer the GLASS build when present (dev checkout): PadRIO
-                    # makes the cockpit buttons mouse-clickable; the pod build's
-                    # clicks are a no-op.  Player zips ship only build\\.
-                    "set GAME=build\\Release\\btl4.exe\n"
-                    "if exist \"build-glass\\Release\\btl4.exe\" (\n"
-                    "  set GAME=build-glass\\Release\\btl4.exe\n"
-                    "  set BT_PLATFORM=glass\n"
-                    ")\n"
-                    "if not exist \"%GAME%\" goto badpath\n"
+                    # ONE unified build (2026-07-21): every layer is in the one
+                    # exe; BT_PLATFORM=glass arms the desktop cockpit (clickable
+                    # buttons / trigger config / bindings.txt keymap).
+                    "set BT_PLATFORM=glass\n"
+                    "if not exist \"build\\Release\\btl4.exe\" goto badpath\n"
                     "if not exist \"content\\" + egg_name +
                     "\" goto badpath\n" +
                     sets +
@@ -834,7 +830,7 @@ class Operator(QMainWindow):
                 "set BT_RELAY=%s:%d\nset BT_LOG=join.log\n"
                 "set BT_START_INSIDE=1\nset BT_DEV_GAUGES=1\n"
                 % (host, self.f_port.value()),
-                "..\\%GAME% -egg %s -net 1501\n" % egg_name,
+                "..\\build\\Release\\btl4.exe -egg %s -net 1501\n" % egg_name,
                 net_tail))
         lan_ip = _detect_lan_ip()
         lan_relay = ("%s:%d" % (lan_ip, self.f_port.value())) if lan_ip else "auto"
@@ -851,7 +847,7 @@ class Operator(QMainWindow):
                 "rem Joining over the INTERNET?  Use join.bat instead.\n",
                 "set BT_RELAY=%s\nset BT_LOG=join.log\n"
                 "set BT_START_INSIDE=1\nset BT_DEV_GAUGES=1\n" % lan_relay,
-                "..\\%GAME% -egg %s -net 1501\n" % egg_name,
+                "..\\build\\Release\\btl4.exe -egg %s -net 1501\n" % egg_name,
                 net_tail))
         with open(os.path.join(out_dir, "play_solo.bat"), "w",
                   newline="\r\n") as f:
@@ -862,7 +858,7 @@ class Operator(QMainWindow):
                 "(ARENA2/DBASE/FOGDAY/...).\n",
                 "set BT_START_INSIDE=1\nset BT_DEV_GAUGES=1\n"
                 "set BT_LOG=join.log\n",
-                "..\\%GAME% -egg ARENA1.EGG\n",
+                "..\\build\\Release\\btl4.exe -egg ARENA1.EGG\n",
                 "echo.\necho The game has exited.  If it closed unexpectedly,\n"
                 "echo send the operator content\\join.log.\npause\n"))
         self.log.appendPlainText(