Settle the local gates for the model-selector round

- ui-model README pair (short-form Model Experience + audited registry
  entry + Known Limitations), recorded in the pairing manifest
- llm-deepseek README pair rebased onto master's version with this PR's
  real deltas (friendly names, 256k, selector consumers) on both sides;
  runtime/ui-conversation READMEs revert to master (their sections
  documented the removed Session state machine and control slot)
- config catalog regenerated for the ui-model roster row
- ModelDirectory.store JSDoc; ui-model files join the TODO(gui) coverage
  deferral lane beside their ui-command/ui-slash siblings

packages/client/runtime/README.md

@@ -22,17 +22,13 @@ SlotsService gives the renderer separate bare observables for `useSessions` and
 
 `SessionManager` retains the latest validated `session/title` control snapshot independently of list and session-instance arrival. Newer event seqs replace older snapshots, title timestamps contribute to list recency, and a subscription baseline discards any retained title beyond its `lastSeq` before the optional folded title arrives. Explicit session removal also clears the retained title. The client-facing `SessionSummary.title` is therefore only the actual durable title; `displayTitle` is always present and falls back through the cwd basename and session id. A cold persisted session keeps that fallback until opening or resuming it causes the host to fold and project its log-backed title.
 
-## Session model selection
-
-Each resident `Session` owns a `modelSelection` snapshot containing the current provider/model target, provider-grouped directory, provider-local failures, and the `idle`/`loading`/`ready`/`selecting`/`error` state. History establishes or refreshes the current target, opening a selector refreshes the directory, and selection failures preserve the last target and usable groups. Directory and selection operations share a monotonically increasing generation so an older response cannot overwrite a newer selection. A reconnect rebuild restores the target reported by the Host without replacing unchanged selection substructure.
-
 ## Model Experience
 
-None, as the session object layer selects the provider/model route used by a later Host request but adds no model-visible content.
+None, as the client runtime hosts browser-side services and the session object layer; nothing here reaches a model request.
 
 #### KV Cache effect
 
-Changing the target can change or invalidate provider-side cache reuse; this package does not alter the prompt prefix itself.
+None; this package neither assembles nor sends a provider request.
 
 ## Known Limitations and Deferred Work