Proposal: ship the authentic single-folder dist layout (docs only, NOT implemented)

The bare-launch crash was a symptom; the cause is that BT411 hands players a
developer tree.  mkdist zips tracked repo paths verbatim, so the dist inherited
build\Release\btl4.exe + content\ -- while the 1995 pod (BTL4OPT.EXE sits
beside BTL4.RES to this day, in content\) and RP411/RP412 all ship ONE folder,
where cwd is right by construction and a double-click just works.

docs/DIST_LAYOUT_PLAN.md sets out the proposed tree, the file-by-file change
(~50 lines total, no game code), what it buys, and the part that actually needs
a decision: the upgrade story.  Four migration options with a recommendation,
plus the wrinkle that decides between them -- the zip root is VERSIONED, so
every version may already land in its own folder, in which case the documented
extract-over-top has never worked and the migration cost is near zero.

Four open questions listed for the other author, including whether the .bat
launchers still earn their keep and whether the pod cabinet's own install shape
should be confirmed against Nick's notes before we call one folder authentic
for the cabinet too.

Not implemented pending that discussion.  The 4.11.560 cwd guard stands either
way and makes both layouts work.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

context/build-and-run.md

@@ -55,7 +55,10 @@ run\run.cmd [EGG]      # default DEV.EGG; cd's to content\ and runs btl4.exe -eg
   two-folder split (`build\Release\btl4.exe` + `content\`) is not a design decision: `mkdist.py`
   zips TRACKED REPO PATHS verbatim, so the dist inherited the repo's developer layout. In the
   authentic single-folder shape cwd is right by construction and a double-click just works, which
-  is why the other games never hit this.
+  is why the other games never hit this. **A proposal to ship the authentic shape is written up
+  in `docs/DIST_LAYOUT_PLAN.md` — PROPOSED, not implemented, awaiting a decision between the
+  authors.** The cwd guard stays either way (it protects the developer tree, where the split is
+  real and permanent).
 - Interactive: **WASD** drive; weapon groups (keyboard, task #43) **1/Space** = lasers, **2** =
   PPCs, **3/Ctrl** = missiles; **X** all-stop; **V** cockpit/chase view. Default egg = `DEV.EGG`
   (map=grass, time=day). Swap mech via the egg's `vehicle=` — **ALL 18 ModelList names