fix(sdk-minimal): make the SDK model argument authoritative

Stop narrowing the standalone DeepSeek adapter to a DSH_MODEL-derived one-entry catalog. The direct adapter already accepts model ids outside its advisory catalog, so retain only the DSH_CONTEXT_WINDOW fallback and let the JSON-RPC initialize model be the single runtime selection.

Remove model mirroring from minimal.py and the packaged smoke. The keyless process now initializes deepseek-v4-pro without DSH_MODEL, while the packaged scenario continues to use its unlisted smoke-model; together they prove both cataloged and arbitrary SDK model arguments reach the adapter directly.

Update the bundle, tutorial, SDK/example references, and owning Agent Notes to keep DSH_MODEL only as minimal.py's optional default input, never as a second value callers must synchronize.

examples/python-sdk-agent/tests/keyless-smoke.e2e.ts

@@ -209,7 +209,6 @@ describe('Python SDK dsh profile keyless smoke', () => {
       cwd: repoRoot,
       env: {
         DSH_HOME: join(root, '.dsh'),
-        DSH_MODEL: 'deepseek-v4-pro',
         DSH_SYSTEM_PROMPT: 'Minimal allowlist prompt.',
         DEEPSEEK_API_KEY: 'keyless-smoke-no-call',
         DEEPSEEK_BASE_URL: `http://127.0.0.1:${address.port}`,