fix(headless): CI green + review-bot findings for the shared composition

Coverage: api-proxy.ts joins the web-transport exclusion block (its
behavior specs moved here with it; the assembled-entry coverage lands with
the GUI test lane). Static: config-catalog regenerated after the log-round
revert shifted a source anchor. Prose brought current per review: the cli
README now describes the one shared composition (and its build
prerequisite), the apiproxy README points at the api-gateway row instead of
the deleted runtime package, and the config-tree agent note's headless
deferral paragraph records what actually landed (bilingual pair
re-recorded).

docs/config-catalog.md

@@ -285,7 +285,7 @@ export interface Config {
 }
 ```
 
-Source: [`packages/client/hmr/src/index.ts:30`](../packages/client/hmr/src/index.ts)
+Source: [`packages/client/hmr/src/index.ts:29`](../packages/client/hmr/src/index.ts)
 
 ## `@deepseek-ai/dsh-code-runtime-worker`