docs: ADR 0002 and NEXT.md 0.4 record the lint toolchain as built

[m-vawter]

Phase 0's exit criterion is that the ADRs match the code. After #94, two records didn't:

• ADR 0002: its dated as-built notes (2026-09-12) say main has no ESLint and CI runs only markdownlint. Following the as-built reconciliation pattern in docs/adrs/README.md, this appends an As built (2026-10-06) subsection with file references and leaves the decision text unchanged.
  • Matches: the ESLint flat config and the slice-boundary rule, five CI jobs, and the pre-commit hook.
  • Differs: typescript-eslint's recommended preset rather than the type-checked ones, and no @nuxt/eslint. vue-tsc runs in CI only, for the reason 0.4 ESLint flat config and vue-tsc in pre-commit #82 gives. The slice rule doesn't see relative imports.
• NEXT.md 0.4: the step text says lint-staged runs vue-tsc. A short "As built" note now says what shipped.

A correction to my #94 review: I said keeping vue-tsc in CI matches ADR 0002. It matches the hackathon golden path, which ADR 0012 made historical. The decision itself asks for enforcement "in CI and pre-commit", so the new section lists it under "Differs".

Closes #126.

Verification

• Every citation was checked against main at 07a353f: eslint.config.mjs, package.json, .husky/pre-commit, .github/workflows/ci.yml, and branch protection through the branch API.
• New prose stays within 80 columns; markdownlint runs in CI.

🤖 Generated with Claude Code

[xcjs]

Approved as non-author. Verified against main at 05fa79d: every cited line reference checks out (eslint.config.mjs 23/44/45/114, ci.yml 10/27/45/63/85, package.json 13/15/20, .husky/pre-commit 1-2). The Matches/Differs split is honest, the slice-rule relative-import caveat is real (no cross-slice relative imports on main), and noting ESLint is not yet a required branch-protection context is a useful flag for a follow-up to #104.