The recipe branch: mods chosen when the game is built, a help key, two books, and the recipe that checks itself

[mplscorwin]

What this changes for the game as shipped: nothing about how it plays. A plain build carries
every mod it carries today, plays online with builds made before this branch, and passes every
existing test. One message is new: a refused join now says "Different game version or mods".

What it adds

1. Mods chosen when the game is built. mods/catalog.tsv declares each mod (its files, what it
   needs, whether online players must match, the tests that need it); mods/default.cfg is the
   shipped set; an uncommitted mods.cfg holds your own (-archipelago, +helpbook, hd3d off).
   A mod that is off is not in the program: its files compile to nothing and src/mods_off.c
   stands in, doing what the game would do had the mod never been written. Its menu lines go; its
   zelda3.ini keys are still accepted. zelda3 --mods says what a build carries. Two builds whose
   game-changing mods differ refuse each other instead of drifting apart.
   • Switchable: story, screenshot, 2D-HD, 3D view (needs 2D-HD), randomizer, Archipelago (needs the
     randomizer), the network. Co-op is not a switch: it is the game now (138 names used by 22
     other files, measured).
   • The rules are mods/SPEC.md (M1 to M21); tests/mods/run.sh checks each in shell (37 tests),
     and --prove-red plants nine faults that must each turn it red.
2. A new mod, off by default: the help key. Ctrl+H opens the player's book at the section for
   what you are doing (the menu, the title or a game over, online, together, a dungeon, outdoors, the
   credits): the Windows help viewer on Windows, the browser elsewhere. tests/coop/helpbook.txt,
   tests/unit/helpbook_url_test.c.
3. Two books, docs/books/manual.md (for players) and docs/books/devguide.md (for modders),
   as numbered game-book sections that each say where to go next. make books builds a Windows help
   file (.chm) for each, web pages, and plain text; the Windows download carries them.
   tools/books.py check refuses a route to nowhere, a section no one can reach, or a page the help
   key needs that is missing.
4. RECIPE.org: the branch as a literate recipe, what each part is, in order, with the command
   and what you should see. Its check blocks are read by two readers that must agree byte for byte,
   and the check runs in CI.
5. CONTEXT-MODELS/: what the work was planned from. Each mod makes its own case with its
   measured numbers; the readers the books were written for; the project's words (yours, Alfred's,
   and Corwin's workshop's, none renamed). contributors/BRYANT.md and ALFRED.md are empty and
   yours to fill, or delete: no one's first person is written for them.
6. The Nintendo Switch build, relanded as a build option (your 6a7984b removed it). It had
   stopped building before it was removed: its Makefile's SRC_DIR pointed at src/, which cannot
   reach snes/ or third_party/. With that fixed, every source compiles for the Switch; it carries
   its own set of mods (mods/switch.cfg: no Archipelago, whose TLS needs the system's OpenSSL, and
   no network, since the port never starts the Switch's sockets). make switch builds
   zelda3.nro, with devkitPro or in its image devkitpro/devkita64, and a new CI job builds it on
   every push without shipping it. Two commits (941b5f5, 693ec85), so it can be dropped alone.

Also: stand-ins for your new A Link to the Past world (8464ead), written from each caller.
Ap_MedallionOpens keeps the original rule (Ether opens Misery Mire, Quake opens Turtle Rock), which
a plain "no" would have broken. BUILDING.md and the README have short sections, and
AI_DISCLOSURE.txt stays true.

How it was checked

• Upstream baseline at 0831a3d: 185/185 tests pass.
• The build matrix (tools/mods_matrix.sh) builds the shipped set, each mod off alone and all off,
  and runs every test in each, skipping nothing; tools/mods_needs.py reads which tests need which
  mod. The first (discovery) run set the catalog's test lists (CONTEXT-MODELS/data/matrix1-*). The
  final run, on this branch's code, is still going as this opens; its results will land as one more
  commit here. Two network tests (net_combat_*) failed once each in the discovery run while the
  machine was busy compiling; the final run is on an idle machine, to tell load from a real need.
• A council read the branch before this pull request (all five are AI sub-agents):
  • a doubt-first critic: 20 rows, 1 block;
  • a reward-first critic: 13 rows;
  • an editor's seat: 12 rows, "looks good to council";
  • two fact-checks of every claim in the player's book, on two model sizes: 8 and 2 false, all
    real.
    All of it was answered in commit 39d79cc, and the fixes closed on one clean QA pass. The block: the recipe's own check said "every check
    passed" after a failure when run with plain sh. It now stops at the first failure, and
    tests/recipe/run.sh proves it.
• CI now also builds every mod off but the help key, runs the URL unit test and the recipe's proof,
  and compiles the help key's Windows file with MinGW.

The first push failed CI, and why

The Archipelago client tests compile src/ap_*.c directly, without make, and the first version of
src/mods.h stopped with an error when the generated header was missing. Fixed in 1426a4f: a file
compiled on its own gets the shipped set (mods/SPEC.md, M22), with a test that compiles every mod's
file alone in a clean tree. Every Linux, Windows, Switch and Archipelago CI step was then run in a
clean clone before the next push (ci-local, which reads the steps from build.yaml itself).

Not checked

• The Switch build running (it builds and links; not run on hardware or an emulator).
• The .chm in the real Windows help viewer. Two readers here agree the files are sound
  (7-Zip, chmlib); a person on Windows 11 is the third.
• The help key on macOS and Windows at run time; tested on Linux, compiled for Windows.

Authorship

Every commit on this branch was made by an AI (Claude, working for Corwin Brust as "Mentat"). By
Corwin's house rule they are authored under his name and each carries
Co-Authored-By: Mentat (for Corwin; claude-opus-5-5); AI_DISCLOSURE.txt says so. If you would
rather they were authored "Claude" like the rest of the history, that is a rebase away.

Mentat (for Corwin; claude-opus-5-5)

[takushieternal]

Noice