Trigger config: root-cause the dead cockpit clicks (missing BT_PLATFORM=glass)

The user held the MFD PROGRAM button and nothing happened (weapons kept
firing).  Diagnosis, verified end-to-end:

- The cockpit mouse handler DID register the click ([cockpit] CLICK addr=0x8
  press) and 0x8 IS a streamed PROGRAM element (EVENT msg 0x9 -> weapon,
  Mfd1 quad page mask).
- But every launch ran the DEV platform profile (no BT_PLATFORM) ->
  L4CONTROLS=KEYBOARD -> no PadRIO instance -> PadRIO::SetScreenButton
  no-ops (activeInstance NULL) -> the press never entered the RIO queue ->
  ConfigureMappables (id 9) never dispatched -> the mode never flipped ->
  fire keys kept firing.  The config machinery itself was never broken.
- With BT_PLATFORM=glass (the GLASS profile: L4CONTROLS=PAD -> PadRIO), the
  full chain now proves out headlessly:
    [btntest] PRESS 0x8 -> [cfgmap] ENTER session on ERMLaser_1
      mode 0x450421 -> 0x448421 (NonMapping 0x10000 -> Mapping 0x8000)
    [btntest] RELEASE 0x8 -> [cfgmap] EXIT (mode restored)

Landed:
- mechweap.cpp: [cfgmap] BT_FIRE_LOG diagnostics in the real
  ConfigureMappables/ChooseButton handlers (they were silent -- the G-key
  harness had logs but the authentic button path had none).
- L4PADRIO.cpp: BT_BTNTEST="addr,pressPoll,releasePoll" scripted screen-
  button harness through the REAL click seam (EmitButton -> RIO queue ->
  manager drain -> buttonGroup mapping) for headless verification.
- play_solo.bat: prefer the glass build when present AND set
  BT_PLATFORM=glass so PadRIO exists and cockpit clicks work.

Side finding (the user's keymap "flip-flop"): CONTROLS.MAP (btinput, DEV/pod
profile) and bindings.txt (PadRIO, GLASS profile) are two parallel binding
engines; which one runs depends on the platform profile, so the felt keymap
changes with the boot flavor.  Unification pending (user decision).

Awaiting live verification of the full hold-PROGRAM + tap-fire regroup flow.

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

game/reconstructed/mechweap.cpp

@@ -218,6 +218,13 @@ void
 			ConfigureMappablesMessageID,				// 9
 			0);											// active_message_id (direct bind)
 	}
+	// [cfgmap] diagnostic (BT_FIRE_LOG): the session bracket + resulting mode.
+	if (getenv("BT_FIRE_LOG"))
+		DEBUG_STREAM << "[cfgmap] " << ((value < 1) ? "EXIT" : "ENTER")
+			<< " session on " << GetName() << " (elem 0x" << std::hex << element
+			<< ") mode now=0x"
+			<< (unsigned)application->GetModeManager()->GetModeMask()
+			<< std::dec << std::endl;
 }
 
 //
@@ -242,6 +249,10 @@ void
 			mapper->AddOrErase(							// vtbl+0x44 (direct overload)
 				(unsigned int)message->dataContents,	// RAW 1-based
 				(ControlsButton *)&fireImpulse);
+			if (getenv("BT_FIRE_LOG"))
+				DEBUG_STREAM << "[cfgmap] ChooseButton toggle btn 0x" << std::hex
+					<< (message->dataContents - 1) << std::dec
+					<< " on " << GetName() << std::endl;
 		}
 	}
 }