Docs: roadmap Phase 5 status (5a egg builder done; 5b/5c/5d remain)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/BT412-ROADMAP.md

@@ -151,6 +151,16 @@ identical-to-baseline → take RP412's file verbatim, diverged → hand-apply th
   fresh menu; `-egg DEV.EGG` stays unmarshaled (dev shortcut); btconsole.py external
   feed still works; marshaled 2-instance loopback collects both score lines.
 
+> **Status (2026-07-14): FOUNDATION DONE (5a egg builder); 5b/5c/5d remain.** The local
+> egg builder (`game/reconstructed/btl4fe.*`) + front-end mode ship: a zero-argument
+> launch builds `frontend.egg` from the default loadout (verified structurally identical
+> to MP.EGG, GDI-rendered plasma name bitmaps) and boots a playable mission. Remaining:
+> the interactive on-screen catalog menu, the in-process LocalConsole marshal (mission
+> clock + StopMission at expiry + single-binary loop), and the score-intake/results
+> screen — the last is NEW work (BT has no mission-end flow: msgID 0x18 is a stub,
+> `scoreAward=0`; collect kills/deaths from the live Comm-MFD `pilotList` at stop).
+> Details in `context/steamification.md`.
+
 ## Phase 6 — Steam lobby (Workstream C.2)
 
 - **`game/reconstructed/btl4lobby.cpp`** (skeleton: `RPL4LOBBY.cpp` — mechanics