feat(11.1-01): verify src= code blocks and add summer docs:sync

- src= fences name a file, a Go declaration or Example body, or a docs:start region
- confinement: relative clean paths inside the root, no dotfiles or .env,
  no nested go.mod modules, Examples need // Output:, test regions must run
- a drifted or missing snippet is a problem, so docs:build writes nothing
- docs:sync rewrites drifted fence bodies in place
- fences render in figure.code with a source caption; .md fences keep only the language
- bonfire ExampleCall is the first verified example, shown in setup/installation

README.md

@@ -73,6 +73,7 @@ The `migrate`, `migrate:status`, `migrate:rollback`, `serve` and admin commands
 |------|----------|
 | `admin/` | The Vue 3 and TypeScript admin SPA; its build output is embedded by boardwalk. |
 | `cmd/` | The `summer` CLI (`cmd/summer`). |
+| `docs/` | Documentation source; `summer docs:build` renders it into a static site. |
 | `examples/` | Example applications; `examples/hello` is the reference application and workspace. |
 | `internal/` | CLI internals: the build and scaffolding generator, the watch loop and an OpenAPI conversion tool. |
 | `modules/` | The framework modules, one Go package each, listed below. |
@@ -145,6 +146,8 @@ npm --prefix admin run gen:api     # regenerate TypeScript types from admin/open
 
 `summer dev` watches an application's sources and rebuilds its binary on change.
 
+`summer docs:build` renders `docs/` and every module README into a static site under `site/` (use `--out` for another directory, `--check` to validate without writing). Code blocks with a `src=` reference are copies of real source; after changing that source, run `summer docs:sync` to refresh the copies.
+
 ## Design notes
 
 Decisions and background live in [`.planning/notes/`](.planning/notes/), including: