chore: add ESLint, Prettier, EditorConfig (permissive first pass)

[aka-blackboots]

Summary

Adds tooling configuration so contributors can run lint and format locally on demand. No auto-fix run yet, no CI integration yet — those are deliberately separate follow-up PRs to keep this one reviewable.

Files added

File	Purpose
eslint.config.js	Flat config. Recommended JS + typescript-eslint rules, plus a Node-context override for build/config scripts so globals like process / __dirname don't false-positive.
.prettierrc.json	100-col, semi, single-quote, trailing-comma all.
.prettierignore	dist/, examples/dist/, node_modules/, lockfile, excluded catalog/.
.editorconfig	2-space indent, LF line endings, UTF-8, trim trailing whitespace.

devDependencies added

eslint, @eslint/js, typescript-eslint, prettier, globals

Scripts added

• npm run lint → eslint .
• npm run format:check → prettier --check .
• npm run format:write → prettier --write .

Posture (intentionally permissive on this first pass)

Rule	Setting	Why
@typescript-eslint/no-explicit-any	warn	any is widespread; surface but don't block
@typescript-eslint/ban-ts-comment	warn	Door/Window cluster has 18+ ignores (tracked separately)
no-useless-escape	warn	Purely stylistic
no-case-declarations	warn	3 sites; cleanup later
@typescript-eslint/prefer-as-const	warn	2 sites; cleanup later
@typescript-eslint/no-unused-vars	warn (with _-prefix escape hatch)	TypeScript already enforces unused locals via noUnusedLocals; this mirrors as warn

Verification

Command	Result
npm run lint	exit 0, 54 warnings, 0 errors
npm run format:check	exit 1, 116 files differ — expected; this is the auto-fix follow-up PR's scope
npm run build	green

What's deliberately NOT in this PR

• No auto-fix run. Running prettier --write across the codebase produces a ~116-file diff that's a separate, much larger PR to review.
• No CI integration of lint/format. Adding npm run lint to CI right now would gate every PR on warnings the team hasn't agreed to enforce. After the auto-fix lands and the rule posture is tightened, lint goes into CI.

Notes

• globals package was added to feed Node and browser globals into the flat config. It's a well-known peer of typescript-eslint.

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