docs: seed CHANGELOG.md (Keep-a-Changelog format)

Closes Row-2 Phase 3 of the 2026-05-26 estate tech-debt audit chain
for this repo. The 2026-05-26 documentation-debt audit
(hyperpolymath/standards#197) flagged that 180 of 279 estate repos
lacked a CHANGELOG.md (65% gap) — this seed closes that finding here.

The seed:
  - Uses Keep-a-Changelog format with an [Unreleased] section.
  - Buckets the most recent 100 commits by conventional-commit prefix
    (feat/fix/refactor/docs/ci/build) into Added/Fixed/Changed/
    Documentation/CI sections.
  - References standards#206's changelog-reusable.yml + the canonical
    templates/cliff.toml for full-regeneration via git-cliff.

The file is initial — the maintainer can adopt changelog-reusable.yml
in this repo's CI to keep it auto-regenerated, or regenerate manually.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

CHANGELOG.md

@@ -0,0 +1,78 @@
+<!--
+SPDX-License-Identifier: MPL-2.0
+SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell (hyperpolymath)
+-->
+
+# Changelog
+
+All notable changes to `formatrix-docs` will be documented in this file.
+
+This file is generated from conventional commits by the
+[`changelog-reusable.yml`](https://github.com/hyperpolymath/standards/blob/main/.github/workflows/changelog-reusable.yml)
+workflow (`hyperpolymath/standards#206`). Adopt the workflow in this repo's CI to keep this file in sync automatically — see
+[`templates/cliff.toml`](https://github.com/hyperpolymath/standards/blob/main/templates/cliff.toml)
+for the canonical config.
+
+The format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/);
+this project aims to follow [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+
+### Added
+
+- feat(crg): add crg-grade and crg-badge justfile recipes
+- feat: add Stapeln container configuration
+- feat: add UX Justfile with doctor, tour, help-me, assail recipes
+- feat: deploy UX Manifesto infrastructure
+- feat: replace Tauri with Gossamer — gossamer-rs backend (mirror of docmatrix)
+- feat: Gossamer migration — RuntimeBridge, gossamer.conf.json, Tauri→Gossamer conversion
+- feat: add formatrix-bridges crate and missing AST module
+- feat: add CLADE.a2ml — clade taxonomy declaration
+- feat: add mirror.yml workflow for GitLab/Bitbucket mirroring
+- feat: customize fuzz target with repo-specific logic
+
+### Fixed
+
+- fix(ci): bump a2ml/k9-validate-action pins to canonical (standards#85) (#10)
+- fix(ci): sync hypatia-scan.yml to canonical (kill cd-scanner build drift) (#9)
+- fix(ci): adopt canonical hypatia-scan.yml (env.HOME/scanner-layout + Comment-step gate) (#8)
+- fix(ci): bump erlef/setup-beam SHA for ubuntu24 runner support (#5)
+- fix(ci): move secret-scanner Cargo.toml gate from job-level if: to step-level (#6)
+- fix(ci): Resolve workflow-linter self-matching and metadata issues
+- fix: correct email jonathan.jewell → j.d.a.jewell
+- fix: global AGPL-3.0-or-later → PMPL-1.0-or-later replacement
+- fix(license): SPDX AGPL-3.0 → PMPL-1.0-or-later in dotfiles
+- fix: remove duplicate SCM files from root
+
+### Changed
+
+- refactor: migrate 6SCM → 6A2 (.scm → .a2ml format)
+
+### Documentation
+
+- docs: add post-audit status report for M5 sweep
+- docs: add TEST-NEEDS.md (CRG C)
+- docs: add EXPLAINME.adoc — prove-it file backing README claims
+- docs: add SECURITY.md for vulnerability reporting
+- docs: add checkpoint files for state tracking
+- docs: rename to DocMatrix
+- docs: mark FD-M07 complete
+- docs: add v1 ecosystem publish roadmap
+- docs: mark FD-C07 Gist library as done
+- docs: update seam check status after SHOULDs
+
+### CI
+
+- ci(rust): convert rust-ci.yml to thin wrapper (standards#174) (#14)
+- ci: redistribute concurrency-cancel guard to read-only check workflows (#12)
+- ci: bump actions/upload-artifact SHA to current v4 (#4)
+- ci: SHA-pin hyperpolymath validate-actions in dogfood-gate
+- ci: deploy dogfood-gate, fix hypatia-scan, add pre-commit hooks
+
+## Pre-history
+
+Prior commits to this file's introduction are recorded in git history but not formally classified into Keep-a-Changelog sections. To backfill, run `git cliff -o CHANGELOG.md` locally using the canonical [`cliff.toml`](https://github.com/hyperpolymath/standards/blob/main/templates/cliff.toml) — this is one-shot mechanical work.
+
+---
+
+<!-- This file was seeded by the 2026-05-26 estate tech-debt audit follow-up (Row-2 Phase 3); see [`hyperpolymath/standards/docs/audits/2026-05-26-estate-documentation-debt.md`](https://github.com/hyperpolymath/standards/blob/main/docs/audits/2026-05-26-estate-documentation-debt.md). -->