feat(host-runtime,llm-replay): keyless llm seam + replay pacing/consumption handle

BootHostOptions.llm: 'deepseek' | false — false mounts no adapter, boots
keyless, and leaves the llm capability seam open for the embedder to fill
on RunningHost.ctx (now the third sanctioned ctx use, JSDoc + README
amended); an unfilled seam fails loud with NO_ADAPTER at the first stream.

dsh-llm-replay grows two additive surfaces for the web browser e2e lane:
paceMs (validated per-chunk delay so a real transport shows incremental
delivery; abort during a pace wait cancels promptly) and a ReplayHandle
return — dispose() plus assertConsumed(), the teardown check that every
recorded script bound and drained, converting silent fixture underruns
into diagnostics. Existing callers updated; config catalog regenerated.

docs/config-catalog.md

@@ -616,6 +616,8 @@ export interface Config {
   childFiles?: string[]
   /** Optional replay-only provider catalog; absent or empty selects catch-all waterfall replay. */
   providers?: ReplayProviderConfig[]
+  /** Optional per-chunk pacing delay in ms (see {@link ReplayConfig.paceMs}); absent keeps burst yield. */
+  paceMs?: number
 }
 
 /** One provider route exposed by the replay adapter. */
@@ -641,7 +643,7 @@ export interface ReplayModelConfig {
 }
 ```
 
-Source: [`packages/support/llm-replay/src/index.ts:387`](../packages/support/llm-replay/src/index.ts)
+Source: [`packages/support/llm-replay/src/index.ts:453`](../packages/support/llm-replay/src/index.ts)
 
 ## `@deepseek-ai/dsh-llm-retry`