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

scripts/verify-package-readme-model-experience.ts

@@ -57,6 +57,7 @@ const SENTENCE_MODEL_EXPERIENCE: Readonly<Record<string, SentenceContract>> = {
   'packages/client/ui-conversation': { kind: 'none', reason: 'Browser-side UI plugin layer; registers no model surface.' },
   'packages/client/ui-slash': { kind: 'none', reason: 'Browser-side UI plugin layer; registers no model surface.' },
   'packages/client/ui-command': { kind: 'indirect', reason: 'The dispatch paths trigger the host command.execute RPC; each command handler\'s host package owns any model-visible effect.' },
+  'packages/client/ui-model': { kind: 'indirect', reason: 'Selection routes session.selectModel; the host snapshots the target at the next prompt-assembly boundary and owns the model-visible effect.' },
   'packages/client/ui-question': { kind: 'indirect', reason: 'The package mounts dsh-tool-ask-user; that tool owns the model-visible schema and answer rendering.' },
   'packages/client/ui-trajectory': { kind: 'none', reason: 'Browser-side UI plugin layer; registers no model surface.' },
   'packages/client/ui-workspace': { kind: 'none', reason: 'Browser-side UI plugin layer; registers no model surface.' },