chore: align CI to the hardened canon, add AGENTS.md

[Unisay]

Brings this fork in line with the shared tooling canon and gives the AI coding agents a single source of truth.

CI (.github/workflows/ci.yml):

• Drop accept-flake-config = true. It let a PR's own flake nixConfig inject extra substituters and keys, which is a supply-chain risk; the caches are already pinned in extra_nix_config, so nothing is lost.
• luacheck now runs --std lua51 --no-unused-args instead of --std min. lua51 matches the actual target (it knows math.pow/math.atan2, which min flags), and --no-unused-args tolerates the curried fallback args the native FFI stubs ignore.
• Run the test step as bash ./scripts/test so it no longer depends on the file's execute bit.

AGENTS.md + CLAUDE.md:

• AGENTS.md is the one instruction file the coding agents read natively (Codex, Cursor, Copilot, Gemini CLI, Aider): the build/test/lint commands, the Lua 5.1 constraints, the FFI parenthesisation rule, and the toolchain pins.
• CLAUDE.md is a one-line @AGENTS.md import so Claude Code reads the same file instead of a second copy that drifts out of sync.

It also drops the dead .eslintrc.json, package.json left over from the JavaScript build; the toolchain is spago plus nix now.

Tooling and docs only, no src/ change, so there is no tag or package-set bump.

Verification

luacheck passes locally with --std lua51 --no-unused-args src/; the build runs green in CI.

[Copilot]

Pull request overview

Aligns this fork’s CI and contributor/agent documentation with the shared “hardened canon” tooling approach, consolidating AI-agent guidance into a single authoritative file.

Changes:

• Harden Nix CI configuration and adjust luacheck settings for Lua 5.1.
• Add AGENTS.md as the primary agent instruction source, and make CLAUDE.md import it.
• Remove legacy JavaScript tooling config (package.json, .eslintrc.json) that’s no longer used.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
.github/workflows/ci.yml	Removes accept-flake-config, updates luacheck flags, and runs test script via bash when present.
AGENTS.md	Introduces consolidated build/test/lint/toolchain and Lua/FFI constraints for coding agents.
CLAUDE.md	Imports AGENTS.md to avoid instruction drift.
package.json	Deletes unused Node/pulp/eslint-era configuration.
.eslintrc.json	Deletes unused ESLint configuration.

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