feat(config): e2e proof, public README, calibrated gates

[msalvatti]

Summary

Closes Phase 6 (integration-docs-dogfood): proves the shipped package end to end and finishes the public documentation. No public API changes; the frozen surface from Phases 0 to 5 is unchanged. This phase adds an e2e suite that boots a realistic NestJS fixture through the built artifact, the complete public README, the first-release changelog entry, recalibrated size budgets, and the full pre-publish gate chain.

What changed

• e2e suite against the built package. test/e2e/ boots a fixture application (server, database, redis, log namespaces per the spec example integration) through the compiled dist/*.cjs artifacts, resolved via moduleNameMapper in jest.e2e.config.ts (never src/ aliases). Three specs, five tests: success boot with typed ConfigService reads and default resolution, aggregated-failure boot pinning the issue count and asserting no raw values leak into the report, and a forRootAsync composition of a process.env-shaped source with an injected fixture secrets provider. @nestjs/testing only, no network port binding, maxWorkers: '50%'.
• Complete public README. Badges, features, installation with a peer-requirements table, quick start (snippets lifted verbatim from the compiled test/e2e/fixtures, each with a source reference comment), full API reference covering every exported symbol of both subpaths (defineEnv, BymaxConfigModule.forRoot/forRootAsync plus the options table, ConfigService get/getAll/has, BymaxConfigValidationError/ConfigIssue, ConfigErrorCode, the BYMAX_CONFIG/BYMAX_CONFIG_OPTIONS tokens, and the type utilities), the error-code catalog, the testing guide, design principles, and known limitations.
• CHANGELOG 0.1.0 entry. Keep a Changelog format, listing the full shipped public surface.
• Recalibrated size budgets. check-size.mjs budgets set to roughly 1.3x the measured brotli baseline (root 4.06 KiB to 5.25 KiB, testing 5.24 KiB to 7 KiB), inside the 1.2x to 1.5x tripwire band, with the baseline and date recorded in the script comment.
• Full prepublishOnly gate. prepublishOnly now chains typecheck, lint, test:cov:all, build, size, dogfood. CI gained an e2e step after the build.

Verification

All commands green from a clean worktree:

• pnpm prepublishOnly: typecheck, lint, test:cov:all (126 unit tests, 100% line/branch/function/statement), build, size (both subpaths PASS), dogfood (both subpaths resolve in ESM and CJS through the exports map, tarball contents clean).
• pnpm build && pnpm test:e2e: 3 suites, 5 tests pass against the built artifact.
• node scripts/dogfood-smoke-test.mjs: all assertions pass.
• Size: root 4.06 KiB brotli (budget 5.25 KiB), testing 5.24 KiB brotli (budget 7 KiB).
• Invariant greps print nothing: no em dashes and no phase/task references in README.md, CHANGELOG.md, src/, or .github/.

Follow-ups

• Phase 7 (mutation-hardening-release): Stryker survivor analysis to the break-95 threshold and the v0.1.0 provenance publish.

[Copilot]

Pull request overview

This PR closes Phase 6 by adding an end-to-end (e2e) verification suite that boots a realistic NestJS fixture against the built dist/ artifacts, publishing a complete public README + initial changelog entry, and tightening release/CI gates (size + dogfood + e2e).

Changes:

• Add e2e fixtures/specs plus a dedicated Jest config to run against compiled dist/*.cjs artifacts.
• Expand public documentation (README) and add the initial 0.1.0 changelog entry.
• Update release gates and CI to include dogfood verification and an e2e step after build.

Reviewed changes

Copilot reviewed 19 out of 19 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
tsconfig.e2e.json	TS config for compiling e2e tests.
test/e2e/fixtures/valid-source.ts	Valid env-source fixture for success-path boot.
test/e2e/fixtures/secrets.provider.ts	Injectable fixture secrets provider for async composition.
test/e2e/fixtures/secrets.module.ts	Nest module wrapper to import/export the secrets provider.
test/e2e/fixtures/incomplete-source.ts	Invalid env-source fixture for aggregated-failure boot.
test/e2e/fixtures/feature.provider.ts	Fixture consumer demonstrating typed ConfigService access.
test/e2e/fixtures/env.schema.ts	Zod schema fixture mirroring the documented integration shape.
test/e2e/config-boot-success.e2e-spec.ts	Success-path e2e boot specs against built artifacts.
test/e2e/config-boot-failure.e2e-spec.ts	Failure-path e2e specs asserting aggregated/value-free errors.
test/e2e/config-boot-async.e2e-spec.ts	Async forRootAsync composition e2e spec.
scripts/check-size.mjs	Recalibrate brotli size budgets and record calibration history.
README.md	Complete public README: features, quick start, API reference, catalog, testing, etc.
package.json	Add test:e2e script and extend prepublishOnly gate chain to include dogfood.
jest.e2e.config.ts	New Jest config mapping package imports to dist/*.cjs for e2e runs.
docs/tasks/README.md	Mark Phase 6 as complete in the tasks index and update totals.
docs/tasks/phase-06-integration-docs-dogfood.md	Mark all Phase 6 tasks complete and append completion log.
docs/development_plan.md	Update dashboard to reflect Phase 6 completion and overall progress.
CHANGELOG.md	Add initial 0.1.0 section documenting the shipped surface.
.github/workflows/ci.yml	Add e2e step after build/size in CI.

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[Copilot]

Pull request overview

Copilot reviewed 19 out of 19 changed files in this pull request and generated no new comments.