[Grivn]

What

When Ollama is running but the configured model is missing, embed --status currently reports embedding_available: true and recall silently loses vector similarity. Status now checks the selected model with a small synthetic embedding request; the legacy ollama_available field retains its existing provider-availability meaning. A failed query embedding prints one actionable stderr warning while recall still returns its normal JSON results.

The extra model probe is limited to the explicit status command. Normal recall keeps its existing request count. Status can load the model and may incur a provider request charge; no stored memories are sent. English and Chinese usage docs explain the distinction between model availability and stored coverage.

Why

Fixes #172. Discovery success alone does not establish that the selected model can produce a vector, even when stored embedding coverage is 100%.

Validation

• Reproduced the false status and silent fallback with failing regressions before the fix.
• Local HTTP tests cover Ollama and OpenAI-compatible providers, missing/malformed/empty vectors, unavailable discovery, providers without a models route, explicit model overrides, and 100% stored coverage.
• Recall tests cover compact, brief and verbose projections, retained lexical results, healthy vector similarity, one warning per failure, no echoed provider content, and no extra recall requests.
• make test (including go vet ./...) and go build -o mnemon . pass.
• Built-CLI smoke test with a temporary store and local mock: missing model reports false availability at 100% coverage, recall preserves its result with a stderr warning, and healthy embedding restores similarity without warnings. No real provider calls.

Release-note impact: embedding diagnostics now detect unusable selected models; failed query embeddings are visible without breaking recall JSON output.

Checklist

• Deterministic tests pass (make test)
• Relevant CLI behavior verified with a focused built-product smoke test; Agency process/Docker boundaries are unaffected
• New/changed behavior is covered by tests
• English and Chinese usage documentation updated
• User-facing release-note impact described