docs: how to set up, run and publish this tree

The setup is unusual enough to need its own page, and the facts were
scattered across scratch.md, CLAUDE.md and publish.sh: the mod is developed
inside a copy of a commercial game, so the dev tree deliberately has no
remote and publishing means rebuilding a filtered repo and force-pushing
that instead.

docs/00-dev-setup.md covers the two-tree arrangement and which one you are
in, prerequisites and why the game must be an extracted folder rather than
a .love (ffi.load goes through the OS loader), building a dev tree from
scratch including the vanilla-0.4.2 baseline tag and the one main.lua line,
the everyday commands, the save location, reading the [speech] console and
the startup self-test, and the publish flow with its leak check.

Linked from CLAUDE.md and the docs index. No code change.

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

accessibility/docs/README.md

@@ -9,6 +9,7 @@ living handoff document: current state, every bug found and why, and the traps.
 | Doc | Contents |
 |---|---|
 | [scratch.md](scratch.md) | **Start here.** Working state, bugs found, gotchas, keymap, how to run the testbed. |
+| [00-dev-setup.md](00-dev-setup.md) | **Setting up.** The two trees, prerequisites, building the dev tree, everyday commands, publishing. |
 | [01-architecture.md](01-architecture.md) | How the game is built: states, console, level model, keybindings. |
 | [02-hooking-strategy.md](02-hooking-strategy.md) | How the mod attaches with (near) zero edits to game files. |
 | [03-implementation-plan.md](03-implementation-plan.md) | The original six-phase plan, with outcomes. |
@@ -17,7 +18,7 @@ living handoff document: current state, every bug found and why, and the traps.
 
 ## Status
 
-**Phases 0–5 complete.** 23 state descriptors, 5 patches, 26/26 testbed checks,
+**Phases 0–5 complete.** 23 state descriptors, 5 patches, 34/34 testbed checks,
 history unit tests passing.
 
 **Game-file footprint: one line in `main.lua`.** Verify at any time: