docs(ci): retire stale Blacksmith references → github-hosted macos-15 (cost) (#35)

#34가 runner를 blacksmith-6vcpu-macos-15 → macos-15(github-hosted)로 전환(비용 과다·
오너 지시)했으나 ci.yml 헤더 주석 + CLAUDE.md 'builds run on Blacksmith' 섹션이 아직
Blacksmith를 가리키는 드리프트가 남아 재도입 위험이 있었음. SSOT를 현실(github-hosted·
PUBLIC repo macOS 무료)에 맞춰 정리. CLAUDE.md CI 섹션은 commons do/dont 형식으로 변환.

Co-authored-by: dancinlife <mk55911@proton.me>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: 3 people

.github/workflows/ci.yml

@@ -1,15 +1,16 @@
-# gamebox CI — build + test on a Blacksmith cloud Apple-Silicon runner.
+# gamebox CI — build + test on a GitHub-hosted Apple-Silicon macOS runner.
 #
 # WHY: gamebox is Apple-native (Win32 PE loader + D3DMetal), so its hexa source
 # compile + the apple-only test suite need a macOS host. Running that locally on
 # the dev Mac (242+ perf modules + 8 test files) spikes memory and crashes the
-# machine. Offloading to Blacksmith's native Apple-Silicon runner
-# (blacksmith-6vcpu-macos-15) keeps every build off the local Mac — the dev box
-# only ever does `git push`.
+# machine. Offloading to a cloud macOS runner keeps every build off the local
+# Mac — the dev box only ever does `git push`.
 #
-# Runner pin: macos-15 (NOT -26) mirrors the hexa-lang release.yml rationale —
-# the SDK baseline rides the builder, and macos-15 keeps the Mach-O min-OS floor
-# stable.
+# Runner: github-hosted `macos-15` (Apple-Silicon). gamebox is a PUBLIC repo, so
+# GitHub-hosted macOS minutes are FREE — this replaced the paid Blacksmith runner
+# (`blacksmith-6vcpu-macos-15`) on owner instruction to stop CI cost. Pin to
+# macos-15 (NOT -26): the SDK baseline rides the builder, and macos-15 keeps the
+# Mach-O min-OS floor stable (mirrors the hexa-lang release.yml rationale).
 #
 # The hexa toolchain is the released binary (gamebox is a downstream consumer,
 # not the compiler repo), installed verbatim via the canonical one-liner.

CLAUDE.md

@@ -57,33 +57,12 @@ without the engine checked out.
 Run via `bash .harness-engine/bin/harness <cmd>` (or, with an external tsx,
 `HARNESS_REPO_ROOT="$PWD" <tsx> .harness-engine/cli/index.ts <cmd>`).
 
-## CI — builds run on Blacksmith, NOT locally
+## CI — cloud macOS runner, NOT local
 
-gamebox is Apple-native (Win32 PE + D3DMetal), so its hexa compile + the
-apple-only test suite need a macOS host. Running that locally (242+ perf
-modules + 8 test files) spikes memory and **crashes the dev Mac** — so CI runs
-on a Blacksmith cloud Apple-Silicon runner instead.
-
-- **Workflow** — `.github/workflows/ci.yml`, job `build-test`, on every
-  push to `main`/`master` + every PR + `workflow_dispatch`.
-- **Runner** — `blacksmith-6vcpu-macos-15` (native Apple-Silicon cloud Mac).
-  Pinned to `macos-15` (NOT `-26`) — same rationale as hexa-lang `release.yml`:
-  the Mach-O min-OS baseline rides the builder SDK, so the pin keeps it stable.
-  same-org (`dancinlab`) Blacksmith is already enabled (hexa-lang uses it), so
-  no extra activation is needed.
-- **Toolchain** — the released `hexa` binary, installed via the canonical
-  one-liner (`install.sh` → `~/.hx/bin`). gamebox is a downstream consumer, not
-  the compiler repo, so it installs the release — it does not build hexa.
-- **What it runs** — `hexa run <file> self-test` over the 8 `[test].files` in
-  `hexa.toml` (NOT `hexa test`, which runs `@test` fns — these files are
-  `self_test()`/`main()` and would pass vacuously); then the native i386
-  interpreter test (`native/i386_cpu_test`, the E3 first-execution gate, clang
-  on the runner); then a gamebox CLI smoke (`status` / `selftest --quick`,
-  warn-only since D3DMetal SDK is absent on the runner).
-
-**Rule for working here**: don't run heavy `hexa test` / builds on the local
-Mac — just `git push` and let Blacksmith build. The dev box should only ever
-push. Check results with `gh pr checks` / `gh run list`.
+- do: build on GitHub-hosted `macos-15` (Apple-Silicon) via `.github/workflows/ci.yml` job `build-test` (push to `main`/`master` + PR + dispatch); gamebox is PUBLIC so these macOS minutes are FREE.
+- do: just `git push` then check `gh pr checks` / `gh run list` — CI installs released `hexa`, runs the 8 `self-test` files + native i386 (`i386_cpu_test`) + Metal/D3D11 substrate smokes.
+- dont: use the paid Blacksmith runner (`blacksmith-6vcpu-macos-15`) — removed on owner instruction for cost (deliberate per-repo override of the `blacksmith-ci` default).
+- dont: run heavy `hexa test` / full builds on the dev Mac (242+ perf modules crash it); use `hexa test` for the suite (vacuous — use `hexa run <file> self-test`); unpin from `macos-15`.
 
 ## Quick reference