feat(release): auto-generate release notes from Conventional Commits (#78)

The release body was a static 'Installation + Binaries' template — every
release looked identical with zero mention of what changed. Append a
'What's Changed' section generated from `git log <prev-tag>..<version>`,
grouped by conventional-commit type (Features / Bug Fixes / Performance /
Refactors / Docs / Tests / Chores / CI), with a Full Changelog compare
link.

Skipped on the first release (no prior tag to compare). Non-conventional
commits are dropped — CLAUDE.md already enforces the convention so this
should be rare, and silence is better than a misleading row.

Codifies the pattern in docs/HARNESS.md so the next agent that goes to
edit release notes manually finds the generator step instead.

Author: fullstackjam

.github/workflows/release.yml

@@ -180,6 +180,7 @@ jobs:
 
       - name: Write release notes
         run: |
+          # Static template — installation + binaries.
           cat > release_notes.md << 'EOF'
           ## Installation
 
@@ -196,6 +197,35 @@ jobs:
           EOF
           sed -i 's/^          //' release_notes.md
 
+          # Auto-generated changelog from Conventional Commits since the
+          # previous tag, grouped by type. Non-conventional commits are
+          # intentionally dropped — they should be rare (CLAUDE.md enforces
+          # the convention) and silence is better than a misleading row.
+          # Skipped entirely on the first release (no prior tag).
+          VERSION="${{ needs.detect-release-type.outputs.version }}"
+          PREV_TAG=$(git describe --tags --abbrev=0 "${VERSION}^" 2>/dev/null || echo "")
+          if [ -n "$PREV_TAG" ]; then
+            {
+              echo ""
+              echo "## What's Changed"
+              echo ""
+              for entry in "feat:Features" "fix:Bug Fixes" "perf:Performance" "refactor:Refactors" "docs:Docs" "test:Tests" "chore:Chores" "ci:CI"; do
+                prefix="${entry%%:*}"
+                heading="${entry#*:}"
+                lines=$(git log --pretty='format:- %s' "${PREV_TAG}..${VERSION}" | grep -E "^- ${prefix}(\(|:)" || true)
+                if [ -n "$lines" ]; then
+                  echo "### ${heading}"
+                  echo ""
+                  printf '%s\n' "$lines"
+                  echo ""
+                fi
+              done
+              echo "**Full Changelog**: https://github.com/${{ github.repository }}/compare/${PREV_TAG}...${VERSION}"
+            } >> release_notes.md
+          fi
+          echo "----- generated release_notes.md -----"
+          cat release_notes.md
+
       - name: Create Release
         uses: softprops/action-gh-release@v2
         with:

docs/HARNESS.md

@@ -52,6 +52,7 @@ Three regulation categories:
 | Behav. | L5 destructive (real installs) | release tags, manual dispatch | `make test-destructive` |
 | Behav. | curl\|bash smoke (install.sh + mock server) | every PR | `.github/workflows/test.yml` `curl-bash-smoke` job |
 | Behav. | Auto-release sensor — tag + dispatch `release.yml` when unreleased commits trip a threshold (`>=5 feat/fix`, `>=7 days + new`, or any `fix:` for patch fast lane) | push to `main` | `.github/workflows/auto-release.yml` |
+| Behav. | Release notes — Conventional Commits since previous tag, grouped by type (Features / Bug Fixes / etc) + Full Changelog link, appended to the install-instructions template | tag push or `workflow_dispatch` | `.github/workflows/release.yml` (`Write release notes` step) |
 | Behav. | Old-CLI compat (previous release × current mock server) | every PR | `.github/workflows/test.yml` `cli-compat` job |
 | Feedfwd. | Agent conventions | every AI turn | `CLAUDE.md`, `AGENTS.md` |
 | Feedfwd. | Skills | model-loaded | `.claude/skills/*` |