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/ui-model/src/client/directory.ts

@@ -27,6 +27,7 @@ export interface ModelDirectoryState {
 
 /** One session's shared directory controller; disposed with the session scope. */
 export class ModelDirectory {
+  /** The shared snapshot both entries render from (uSES-safe store). */
   readonly store: SnapshotStore<ModelDirectoryState> = createSnapshotStore<ModelDirectoryState>({
     current: null, groups: [], failures: [], status: 'idle', error: null,
   })