docs(changelog): customizable welcome prompt

CHANGELOG.md

@@ -10,6 +10,22 @@ CalVer image tags (`stable-YYYY.MM.N`, `dev-YYYY.MM.N`) are produced for every C
 
 ## [Unreleased]
 
+### Added
+
+- Customizable analyst welcome prompt (`CLAUDE.md` generated by `da analyst setup`). Default ships at `config/claude_md_template.txt` (now Jinja2 syntax). Admins override per instance via the `/admin/welcome` editor or `PUT /api/admin/welcome-template`. New endpoint `GET /api/welcome` returns the rendered prompt for the calling user, with `marketplaces` filtered by RBAC. See `docs/welcome-template.md` for the full placeholder reference.
+- `POST /api/admin/welcome-template/preview` — renders arbitrary template content against the calling admin's live context without persisting. Backs the editor's Preview button.
+- DuckDB schema v21: `welcome_template` singleton table for the per-instance override. Auto-migration v20→v21 on first start.
+- New `instance.sync_interval` setting in `instance.yaml` (default `"1 hour"`) — surfaced in the welcome prompt as `{{ sync_interval }}`.
+
+### Changed
+
+- **BREAKING (CLI):** `da analyst setup` no longer accepts `--sync-interval`. The cadence shown in the analyst `CLAUDE.md` now comes from the server's `instance.yaml`. Operators who relied on the flag should set `instance.sync_interval` in `instance.yaml` instead.
+- `da analyst setup` now fetches `CLAUDE.md` from `GET /api/welcome` instead of substituting placeholders client-side. The CLI keeps a minimal embedded fallback for older servers without the endpoint and prints a stderr warning when the fetch fails for any reason other than 404.
+
+### Fixed
+
+- Pre-existing bug: the CLI's `_get_instance_name` parsed `instance_name` from `/api/health`, but `/api/health` only ever returned `{"status": "ok"}`, so the configured `instance.name` was never propagated to the analyst's `CLAUDE.md`. The new server-side render path uses `app.instance_config.get_instance_name()` directly.
+
 ## [0.30.1] — 2026-05-02
 
 ### Security