docs: prepare v0.1.0-alpha.4 release notes

[FernandoAbishai]

Context

Prepare the v0.1.0-alpha.4 public release notes from the qualified alpha.3-to-main change range. Product versions remain 0.1.0, and this PR does not create or publish a tag or GitHub release.

Changes

• add the exact v0.1.0-alpha.4 changelog section while preserving Unreleased and alpha.3 history;
• document the creator workflow, reliability, and release-integrity changes since alpha.3;
• update the release-notes smoke to validate the repository's exact alpha.4 dry-run and publication-required selection while preserving generic synthetic lifecycle fixtures.

Validation

• release-notes smoke: PASS
• release identity smoke: PASS
• release metadata smoke: PASS
• public-release smoke: PASS
• release-workflow smoke: PASS
• direct dry-run/publication selector: exact v0.1.0-alpha.4, non-empty
• monotonic alpha4 tag validation: PASS
• git diff --check: PASS

Scope

Only CHANGELOG.md and scripts/smoke-release-notes.js are changed. No production behavior, release-selection implementation, package versions, qualification evidence, release workflow, tag, or GitHub Release was changed or created.

Do not merge.

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