ci(#462): add durable next publish pipeline (#687)

Durable @next integration-line publish: on next pushes, compute <patch+1>-next.<pipeline#> prerelease versions (in-CI, uncommitted) and publish @mosaicstack/* under the next dist-tag; gateway image sha-only on next. Strict guardrails: next-only, never writes latest, never tags from next; main path unchanged. PR-event CI 1631 fully green + review-of-record APPROVE (head b1a887a2). Guardrails independently verified.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/guides/dev-guide.md

@@ -211,6 +211,17 @@ pnpm format:check && pnpm typecheck && pnpm lint
 
 A pre-push hook enforces this mechanically.
 
+### CI Publish Channels
+
+Woodpecker `.woodpecker/publish.yml` keeps stable and integration-line artifacts separate:
+
+| Source                            | npm packages                                                                                                  | Gateway image                                                                            |
+| --------------------------------- | ------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------- |
+| `main` push/manual or release tag | committed package versions published to Gitea npm without changing the dist-tag workflow                      | `gateway:sha-<short>` plus `gateway:latest` on `main`, and the release tag on tag events |
+| `next` push/manual                | CI-computed prereleases, `<target-stable>-next.<CI_PIPELINE_NUMBER>`, published with `npm publish --tag next` | `gateway:sha-<short>` only                                                               |
+
+`next` never publishes npm `latest` or Docker `latest`. The next npm publish step verifies that `@mosaicstack/mosaic@next` resolves to the computed prerelease before the pipeline can pass.
+
 ---
 
 ## Adding New Agent Tools