fix(host): opt in to model titles from web

packages/host/runtime/README.md

@@ -1,6 +1,6 @@
 # @deepseek-ai/dsh-host-runtime
 
-Host runtime assembly for `dsh`: `bootHost` composes the core plugin spine (LLM service + DeepSeek adapter, sessions with JSONL persistence, immediate fallback titles and first-message model summaries, system prompt, tools, agents, agent loop, workspace instructions, local bash), `createApiProxy` implements the [`dsh-host-apiproxy`](../apiproxy/README.md) contract over that composition, and `startHost` is the one-step shell seam returning `{ api, handler, defaults, ctx, dispose }`.
+Host runtime assembly for `dsh`: `bootHost` composes the core plugin spine (LLM service + DeepSeek adapter, sessions with JSONL persistence and immediate fallback titles, optional first-message model summaries, system prompt, tools, agents, agent loop, workspace instructions, local bash), `createApiProxy` implements the [`dsh-host-apiproxy`](../apiproxy/README.md) contract over that composition, and `startHost` is the one-step shell seam returning `{ api, handler, defaults, ctx, dispose }`.
 
 Which plugins mount and with what defaults is decided only here — shells must not `ctx.plugin` to alter the assembly. `RunningHost.ctx` is a formal seam with exactly two sanctioned uses: mounting protocol front-door plugins (e.g. a future `dsh acp`) and headless session-event subscription; consuming clients must not bypass `api` through it.
 
@@ -14,7 +14,7 @@ Which plugins mount and with what defaults is decided only here — shells must
 | `model` | `'deepseek-v4-flash'` | Default model id, same single source as `provider`. |
 | `cwd` | `process.cwd()` | Default project directory for a session whose create request omits `cwd`. |
 | `sessionTitle` | 5 words / 40 fallback bytes / 80 accepted bytes | Deterministic fallback and accepted-title limits. |
-| `sessionTitleLlm` | 5 words / 10 CJK chars / 4,096 input bytes / 64 output tokens / 60 s | First-message model-title policy. An omitted route inherits the logged main-request provider and model. |
+| `sessionTitleLlm` | disabled | `true` enables the 5-word / 10-CJK-character, 4,096-input-byte, 64-output-token, 60-second first-message policy; an explicit config overrides it. An omitted route inherits the logged main-request provider and model. |
 
 ## ApiProxy implementation notes
 
@@ -22,11 +22,11 @@ Unary methods take the narrow `RpcRequest<P>` and echo `request.rpcId`; a prompt
 
 ## Model Experience
 
-Indirectly, through the non-blocking first-message title request owned by [`dsh-session-title-llm`](../../session-title/session-title-llm/README.md), the provider/model defaults injected into created and resumed agents, and the other model-facing plugins `bootHost` mounts. When `workspaceContext` is enabled, each agent-loop instance freezes the applicable workspace instructions into its logged request prefix; the owning package documents the exact [model-visible framing](../../context/workspace-context/README.md#prompt-shape).
+Indirectly, through the non-blocking first-message title request owned by [`dsh-session-title-llm`](../../session-title/session-title-llm/README.md) when `sessionTitleLlm` is enabled, the provider/model defaults injected into created and resumed agents, the other model-facing plugins `bootHost` mounts, and the logged [workspace-instruction prefix](../../context/workspace-context/README.md#prompt-shape) when `workspaceContext` is enabled.
 
 #### KV Cache effect
 
-No main-request invalidation; the auxiliary title request has its own cache behavior and the conversation prefix remains unchanged.
+No main-request invalidation; when enabled, the auxiliary title request has its own cache behavior and leaves the conversation prefix unchanged.
 
 ## Known Limitations and Deferred Work