Use towncrier orphan fragment naming for C0 changes

C0 changes have no branch name, so `main.<type>.md` fragments collide.
Switch to towncrier's `+<slug>.<type>.md` orphan convention and rename
existing `main.*` fragments.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

CLAUDE.md

@@ -19,9 +19,11 @@ blumeops is Erich Blume's GitOps repository for personal infrastructure, orchest
 3. **Classify the change as C0/C1/C2 before starting** (see below) — this determines branching and PR requirements
 4. **Feature branches + PRs for C1/C2** - checkout main, pull, create branch, open PR via `tea pr create`. C0 goes direct to main.
 5. **Check PR comments with `mise run pr-comments <pr_number>`** before proceeding
-6. **Add changelog fragments (all change levels)** - `docs/changelog.d/<branch>.<type>.md`
+6. **Add changelog fragments (all change levels)** - `docs/changelog.d/<name>.<type>.md`
     Types: `feature`, `bugfix`, `infra`, `doc`, `ai`, `misc`
     Applies to C0, C1, and C2 whenever the change is user-visible or noteworthy.
+    - **C1/C2:** Use branch name: `<branch>.<type>.md`
+    - **C0:** Use orphan prefix: `+<descriptive-slug>.<type>.md` (avoids `main.*` collisions)
 7. **Test before applying** - dry runs (`--check --diff`), syntax checks, `ssh indri '...'`
 8. **Wait for user review before deploying** (C1/C2)
 9. **Never merge PRs or push to main without explicit request** (C0 commits to main are fine)

docs/changelog.d/+orphan-fragment-convention.doc.md

@@ -0,0 +1 @@
+Use towncrier orphan fragment naming (`+slug.<type>.md`) for C0 changes to avoid `main.*` collisions.

docs/how-to/agent-change-process.md

@@ -29,7 +29,7 @@ A change where the risk is low enough that problems can be quickly fixed forward
 
 1. Run `mise run ai-docs` to load context
 2. Implement the change directly on main
-3. Add a changelog fragment if the change is user-visible or noteworthy (`docs/changelog.d/<description>.<type>.md`)
+3. Add a changelog fragment if the change is user-visible or noteworthy (`docs/changelog.d/+<descriptive-slug>.<type>.md`)
 4. Commit and push
 
 No feature branch or PR required. If something goes wrong, fix forward with another commit.
@@ -270,7 +270,7 @@ tags:
 - **C0:** Commit directly to main
 - **C1:** Single feature branch, PR early, push often
 - **C2:** Branch named `mikado/<chain-stem>`, Mikado Branch Invariant enforced, `C2()` commit convention, PR early, push after every leaf-node closure
-- **Changelog fragments (all levels):** Add `docs/changelog.d/<name>.<type>.md` for any user-visible or noteworthy change, regardless of change class. C0 includes the fragment in the same commit. C1 includes it during the branch work. C2 includes it in the `finalize` commit.
+- **Changelog fragments (all levels):** Add `docs/changelog.d/<name>.<type>.md` for any user-visible or noteworthy change, regardless of change class. C0 uses orphan fragments (`+<descriptive-slug>.<type>.md`) to avoid `main.*` collisions. C1/C2 use the branch name (`<branch>.<type>.md`). C0 includes the fragment in the same commit. C1 includes it during the branch work. C2 includes it in the `finalize` commit.
 - **Deploy from branches** — C1 and C2 changes deploy from the unmerged branch (ArgoCD `--revision`, Ansible from checkout, etc.). Reset to main after merge.
 - GitOps requires pushing to test — if a pushed commit breaks, revert it promptly
 

docs/tutorials/ai-assistance-guide.md

@@ -58,7 +58,11 @@ EOF
 
 Add a fragment for user-visible changes:
 ```bash
+# C1/C2: use branch name
 echo "Description" > docs/changelog.d/branch-name.feature.md
+
+# C0: use orphan prefix (no branch to name after)
+echo "Description" > docs/changelog.d/+descriptive-slug.feature.md
 ```
 
 Types (file suffix): `.feature`, `.bugfix`, `.infra`, `.doc`, `.ai`, `.misc`