Ensure live provider checks reach the provider

Accept Docker Compose's exact string representation of the fixed 1024-dimensional embedding contract while rejecting every widened or ambiguous value. Entry-level smoke tests now exercise the same environment shape used by the container.

Constraint: The current local Bailian credential still returns 401 for all three capabilities and is not stored in Git.
Rejected: Change the field to an unconstrained integer | would allow a runtime dimension that disagrees with vector(1024).
Confidence: high
Scope-risk: narrow
Directive: Keep the database vector dimension and provider dimension locked together through an ADR-backed migration.
Tested: make verify; 75 backend tests; 14 frontend tests; rebuilt provider-smoke image; normal Compose smoke reached all three provider endpoints.
Not-tested: Successful live provider response remains blocked by external authentication.

backend/tests/unit/test_provider_smoke.py

@@ -1,5 +1,54 @@
+import pytest
+
+from app.core.config import Settings
 from app.ports.model_providers import ModelProviderError, ProviderErrorKind
-from app.tools.provider_smoke import failed_probe
+from app.tools import provider_smoke
+from app.tools.provider_smoke import ProbeResult, failed_probe
+
+
+def test_provider_smoke_settings_accept_compose_embedding_dimension(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    monkeypatch.setenv("EMBEDDING_DIMENSION", "1024")
+
+    settings = Settings(_env_file=None)
+
+    assert settings.embedding_dimension == 1024
+
+
+async def test_provider_smoke_entrypoint_accepts_compose_embedding_dimension(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    workspace_host = "workspace-test.cn-beijing.maas.aliyuncs.com"
+    monkeypatch.setenv("EMBEDDING_DIMENSION", "1024")
+    monkeypatch.setenv(
+        "BAILIAN_OPENAI_BASE_URL",
+        f"https://{workspace_host}/compatible-mode/v1",
+    )
+    monkeypatch.setenv(
+        "BAILIAN_RERANK_BASE_URL",
+        f"https://{workspace_host}/compatible-api/v1",
+    )
+    observed_dimensions: list[int] = []
+
+    def fake_api_key(settings: Settings) -> str:
+        observed_dimensions.append(settings.embedding_dimension)
+        return "test-only-api-key"
+
+    async def successful_probe(settings: Settings, api_key: str) -> ProbeResult:
+        observed_dimensions.append(settings.embedding_dimension)
+        assert api_key == "test-only-api-key"
+        return ProbeResult(capability="test", status="ok")
+
+    monkeypatch.setattr(Settings, "bailian_api_key", fake_api_key)
+    monkeypatch.setattr(provider_smoke, "probe_embedding", successful_probe)
+    monkeypatch.setattr(provider_smoke, "probe_rerank", successful_probe)
+    monkeypatch.setattr(provider_smoke, "probe_chat", successful_probe)
+
+    exit_code = await provider_smoke.async_main()
+
+    assert exit_code == 0
+    assert observed_dimensions == [1024, 1024, 1024, 1024]
 
 
 def test_failed_probe_only_exposes_sanitized_provider_fields() -> None: