feat(core,github-action,github): support custom changelog preamble

[dangreen]

Adds support for a custom changelog preamble — arbitrary markdown inserted into the changelog right after the version header, before the generated sections.

Usage

Config / JS API — a new bump.preamble option; per package in a monorepo via bump.byProject[name].preamble.

Pull request comment — !simple-release/set-preamble followed by the markdown. In a monorepo, pass the full package name (in backticks so GitHub keeps it as text) to target one package:

!simple-release/set-preamble `@your-org/core`

## Core changes

- New plugin system

Multiple per-package comments coexist (newest per package wins); one comment without a name sets a global preamble for the whole release. The command honors the same owner/member/collaborator restriction as set-options.

Notes

• Non-breaking. Rendering reuses the existing preamblePartial — Project.bump just started populating the changelog context's preamble. Per-package targeting reuses bump.byProject (keyed by full package name).
• The GitHub Action itself needs no code change; the feature ships when the action bumps its @simple-release/github-action dependency.
• Tests: core rendering (global + per-package), the comment parser (name / backticks / empty / untrusted author), and suppression of the "Version bump without any changes." fallback when a preamble is set.

[coveralls]

Coverage Report for CI Build 29332536178

Coverage decreased (-0.03%) to 63.11%

Details

• Coverage decreased (-0.03%) from the base build.
• Patch coverage: 43 uncovered changes across 1 file (23 of 66 lines covered, 34.85%).
• No coverage regressions found.

Uncovered Changes

File	Changed	Covered	%
packages/github-action/src/releaser.ts	43	0	0.0%
Total (3 files)	66	23	34.85%

Coverage Regressions

No coverage regressions found.

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Coverage Stats

Relevant Lines:	1046
Covered Lines:	719
Line Coverage:	68.74%
Relevant Branches:	594
Covered Branches:	316
Branch Coverage:	53.2%
Branches in Coverage %:	Yes
Coverage Strength:	10.76 hits per line

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💛 - Coveralls

[Copilot]

Pull request overview

Adds end-to-end support for a user-defined changelog “preamble” (markdown inserted immediately after the version header), configurable via JS/config (bump.preamble, bump.byProject[name].preamble) and via a new PR comment command (!simple-release/set-preamble).

Changes:

• Extend core bump options and changelog template context to carry a preamble, and suppress the “Version bump without any changes.” fallback when a preamble exists.
• Add GitHub Action support for parsing !simple-release/set-preamble comments (global + per-package) and applying them to bump options.
• Update docs/cheatsheet and add tests for preamble rendering and comment parsing.

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
website/src/content/docs/js-api/releaser.mdx	Documents new bump.preamble option (and monorepo usage).
website/src/content/docs/github-action/release-automation.mdx	Documents !simple-release/set-preamble usage for PR comments.
skills/setup-simple-release-action/SKILL.md	Updates setup guidance to mention the new comment command.
packages/github/src/cheatsheet.ts	Adds cheatsheet section for set-preamble and updates restrictions/notes wording.
packages/github-action/src/releaser.ts	Scans PR comments for preambles and merges them into bump options.
packages/github-action/src/conditions.ts	Triggers comment-driven runs for both set-options and set-preamble.
packages/github-action/src/comment.ts	Adds set-preamble command parsing and exports COMMANDS.
packages/github-action/src/comment.spec.ts	Adds vitest coverage for set-preamble parsing behavior.
packages/core/src/project/project.types.ts	Adds preamble?: string to ProjectBumpOptions.
packages/core/src/project/project.ts	Passes preamble into changelog template context.
packages/core/src/project/packageJsonMonorepo.spec.ts	Tests global vs per-project preamble behavior in monorepos.
packages/core/src/project/packageJson.spec.ts	Tests insertion position and placeholder suppression for preamble.
packages/core/src/project/monorepo.types.ts	Allows preamble in byProject bump options typing.
packages/core/src/change-log.ts	Suppresses “no changes” placeholder when a preamble exists.

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[Copilot]

Pull request overview

Copilot reviewed 14 out of 14 changed files in this pull request and generated 4 comments.

[Copilot]

Pull request overview

Copilot reviewed 14 out of 14 changed files in this pull request and generated 2 comments.

[Copilot]

Pull request overview

Copilot reviewed 14 out of 14 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 14 out of 14 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 14 out of 14 changed files in this pull request and generated 3 comments.