Merge remote-tracking branch 'origin/master' into jsonl-packed-chunk-rows

Master removed the stdio demo (#702c8cc30) — accept the deletion; this
branch's packChunks passthrough survives in acp-demo (auto-merged), and
cli-demo/tui-demo arrived from master without one (the follow-up snapshot
PR decides which demos expose the switch). Generated catalogs regenerated
over merged sources; the hand-written session.md durability paragraph
re-weaves this branch's lossless-encoding wording with master's invariant-
companion sentence.

packages/support/llm-replay/src/index.ts

@@ -11,7 +11,7 @@ import { delimiter as pathDelimiter } from 'node:path'
 import type { Context } from 'cordis'
 import { decodeStorageRecord } from '@deepseek-ai/dsh-session'
 import type { SessionEvent } from '@deepseek-ai/dsh-session'
-import type { GenerateOptions, LlmModelInfo, LlmProviderInfo, StreamChunk } from '@deepseek-ai/dsh-llm'
+import type { GenerateOptions, LlmModelContext, LlmModelInfo, LlmProviderInfo, StreamChunk } from '@deepseek-ai/dsh-llm'
 import { LlmAdapter, LlmError, assertNever } from '@deepseek-ai/dsh-llm'
 
 /**
@@ -32,6 +32,8 @@ export interface ReplayModelConfig {
   name?: string
   /** Optional selector description. */
   description?: string
+  /** Optional positive integer context capacity published by the replay adapter. */
+  contextWindow?: number
 }
 
 /** One provider route exposed by the replay adapter. */
@@ -262,6 +264,14 @@ class ReplayAdapter extends LlmAdapter {
     })))
   }
 
+  override resolveModelContext(provider: string, model: string): Promise<LlmModelContext | undefined> {
+    const configured = this.providers.get(provider)
+    /* v8 ignore next -- LlmService only asks about routes registered from this same map. */
+    if (configured === undefined) return Promise.resolve(undefined)
+    const contextWindow = configured.models?.find(candidate => candidate.id === model)?.contextWindow
+    return Promise.resolve(contextWindow === undefined ? undefined : { contextWindow })
+  }
+
   override stream(options: GenerateOptions): AsyncIterable<StreamChunk> {
     return this.replay(options)
   }