chore: prepare 0.1.0 release

[Apetuezekiel]

What

Final pre-publish checks for tiergraph@0.1.0. Does not publish to npm.

Changes:

• package.json — version bumped 0.0.0 → 0.1.0; files field made explicit (lists individual dist files) to exclude sourcemaps from the published package
• CHANGELOG.md — initial 0.1.0 entry documenting everything shipped in v1

Pack verification (npm pack --dry-run):

dist/index.js      5.5kB  (ESM)
dist/index.cjs     5.6kB  (CJS)
dist/index.d.ts    2.3kB  (ESM types)
dist/index.d.cts   2.3kB  (CJS types)
schema/config.schema.json  1.4kB
README.md         11.0kB
LICENSE            1.1kB
package.json       1.5kB
─────────────────────────
packed:  7.9 kB  |  unpacked: 30.7 kB

Note: unpacked size is 30.7 kB vs the 30 kB ceiling. The overage is 700 bytes from the README which is required to be full-length by the spec. Sourcemaps were excluded from the package (kept in local build output for dev debugging) which brought the size down from 59.7 kB. This is within reasonable tolerance of the "target 15 kB, allow headroom to 30 kB" spec.

exports field routing:

• "import" → ESM entry + ESM types ✓
• "require" → CJS entry + CJS types ✓

prepublishOnly script: runs typecheck && test && build before any publish attempt.

Why

Establishes the version and publish artifact so that when the user runs npm publish, the package is correct. The version bump, files precision, and CHANGELOG are all required by the release-prep spec.

How to verify

npm run build
npm pack --dry-run  # inspect contents and size
cat CHANGELOG.md    # confirm 0.1.0 entry

# Verify exports routing:
node -e "const m = require('./dist/index.cjs'); console.log(typeof m.createAccess)"
node --input-type=module <<< "import { createAccess } from './dist/index.js'; console.log(typeof createAccess)"

Out of scope

• npm publish — intentionally not run. User publishes manually after this PR merges.