pod: self-contained bundles - drivers install via the game postinstall

Per Cyd: no operator ever installs anything on a pod by hand. build-pod.ps1
now mirrors the universal inner layout (app/app-xp, vendor, install-core.bat
+ install-rio.ps1 reused verbatim) and bundles the flavor prerequisites
(ViGEmBus / XP .NET+KB+RioGamepadXP). New install-riojoy.bat entry point is
called from the game postinstall.bat: self-elevating, idempotent, add-only.
Deliberately no uninstall step - other podized games may share the drivers,
so they are abandoned in place. Also: deploy scripts must stay pure ASCII
(PS5.1 reads BOM-less UTF-8 as ANSI; an em dash decodes to a smart quote
that terminates strings).

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

docs/PLAN.md

@@ -516,14 +516,24 @@ total across the suite.
   down while game B's starts) instead of the historical silent exit-0; plain
   launches keep the instant-exit behavior. Abandoned mutex (predecessor
   crash) counts as acquired.
-- **`deploy/build-pod.ps1`**: emits the per-game drop-in — `riojoy\` app
-  (flavor-selectable net48/net40, Skia-pruned) + portable `config.json`
-  wrapping the game's profile document verbatim + `start-riojoy.bat`
-  (`--exit-with` prefilled from the profile's first trigger) + README-POD —
-  zipped as `RIOJoy-pod-<name>-<stamp>.zip` (~4.5 MB). Deliberately **no
-  drivers**: pods are provisioned once by the universal package. Verified by
-  building the Descent bundle and round-tripping its emitted config through
-  `ConfigStore.Load`.
+- **`deploy/build-pod.ps1`**: emits the **self-contained** per-game drop-in —
+  nothing is ever installed on a pod by hand. Inner layout mirrors the
+  universal package (`app`/`app-xp`, `vendor`, `install-core.bat`,
+  `install-rio.ps1` reused **verbatim** — no forked install logic), plus the
+  portable `config.json` beside the exe (the game's profile document
+  verbatim), `start-riojoy.bat` (`--exit-with` prefilled from the profile's
+  first trigger), and `install-riojoy.bat`: called from the **game's
+  `postinstall.bat`**, self-elevating, **idempotent** (installs only what's
+  absent — ViGEmBus on net48; .NET 4.0 + KB2468871 + RioGamepadXP via devcon
+  on net40 — and never removes anything). There is deliberately **no
+  uninstall step**: drivers are abandoned in place on game removal, since
+  nothing can know whether another podized game still uses them and idle
+  drivers are harmless. Zipped as `RIOJoy-pod-<name>-<stamp>.zip` (~8.4 MB
+  net48 incl. ViGEmBus). Verified by building the Descent bundle and
+  round-tripping its emitted config through `ConfigStore.Load`.
+  Gotcha for future edits: PS 5.1 reads BOM-less scripts as ANSI, where a
+  UTF-8 em dash decodes into a smart quote that *terminates strings* — keep
+  deploy scripts pure ASCII.
 - ⏳ **Remaining:** on-pod verification of the full launch/handoff cycle
   (launcher → game A → quit → game B); podize a first real game with the
   bundle; revisit the universal zip's `install.bat` framing (dev-setup only)