port-layer papercuts for the playtest: #69 Denkou rename, #71 plasma X=minimize, #157 round-end UX (foreground handoff + lastrun clean-exit markers + bat sign-off rewording); tester-facing open-issues handout (docs/) + field-log anatomy notes

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

context/build-and-run.md

@@ -69,6 +69,23 @@ run\run.cmd [EGG]      # default DEV.EGG; cd's to content\ and runs btl4.exe -eg
   ⚠ **Keep the `if /I "%%P"=="btl4.exe"` guard** — parsing tasklist with `tokens=2` alone reads its
   *"INFO: No tasks are running"* line as a PID and spins forever with nothing running. Full
   investigation, including which windows exit vs merely hide: `phases/phase-12-orphan-processes.md`.
+- **Field-log anatomy — reading a steam night (#157 forensics, 2026-08-10) [T2].** A night's log is
+  a CHAIN of `===== BT411 SESSION` blocks: menu stubs (`args=''`, "first process") alternating with
+  glass generations (`-net 1501 -platform glass`, "relaunched generation"); one glass block = one
+  drop, and boundaries are synchronized across every machine to ±2 s (mission-clock expiry relaunches
+  all peers' menus in the same second). **Stub anatomy:** the steam lobby is CLICK-driven
+  (`steamAction`, btl4fe.cpp), so a menu closed without a click logs exactly **4 boot lines** and
+  exits 0 — a 4-line stub at end-of-night is a player going to bed, NOT a crash (all four machines
+  ended night-14 with identical 4-line stubs at 00:31:2x). 7–8-line stubs = a lobby cycle
+  (`[steamnet] up` + `[lobby] join` + map). `BTCrashFilter` is armed before the first log line and
+  writes a `[crash]` block + module-relative stack on ANY unhandled exception — a silent log end
+  means quit/kill/hang, never an unlogged AV. **`lastrun_<stem>.txt` caveats:** appends stop silently
+  if the file gets locked (the `is_open` guard skips) — a lastrun ending mid-night while the log
+  continues means the file was captured/locked during live troubleshooting, not that the chain died.
+  And the bat sign-off ("The game has exited. If it closed unexpectedly, send…") prints after ANY
+  chain end including a normal quit — it primes players to report quits as crashes; #157 ("did not
+  exit cleanly") was exactly this echo. The arcade-authentic round-end (mission process exits →
+  menu relaunch) itself reads as a crash to first-night players.
 - **Why this is a BT411-only hazard [T1].** The 1995 pod shipped ONE folder — `BTL4OPT.EXE` sits
   next to `BTL4.RES`/`VIDEO\`/`GAUGE\`/`AUDIO\` (it is still there in `content\`) — and RP411/RP412
   keep that shape (`pack-dist.ps1` copies the exe and every asset dir into one dist root). BT411's