feat: redesign around phenotype-driven triage, not variant filtering

A table with filters made the user do the work. Rare disease triage is a different task:
which few variants could explain *this* patient's phenotype, and why. The app now answers
that, and lets a reviewer act on the answer.

Domain
- a case is a proband: a VCF plus the HPO terms observed in the patient (samples -> cases)
- HPO's gene-to-phenotype annotations are loaded as reference data (scripts/load-hpo.py)
- each candidate can be shortlisted or dismissed with a reason and a note

Ranking (app/services/triage.py, 21 tests)
- weighted sum of phenotype match, rarity, consequence severity and the model's score,
  with every component shown next to the candidate
- rarity and consequence filter; phenotype only ranks, because a real diagnosis can sit in
  a gene nobody has annotated yet and filtering on it would hide exactly that case
- ClinVar is deliberately not an input: it appears beside the result as independent
  confirmation, so nothing ranks highly merely because ClinVar already said pathogenic

UI
- the funnel is the headline: variants called -> rare -> coding candidates -> phenotype-matched
- ranked candidates with evidence chips, not a grid of everything; filters are demoted
- a variant panel showing the score breakdown, the matched HPO terms, the raw VEP record and
  links out to Ensembl/gnomAD/ClinVar, with the decision controls
- a printable case report: phenotype, funnel, shortlisted variants with reasons, provenance

API: /cases with phenotypes, /cases/{id}/candidates (funnel + ranked + weights),
/variants/{id}, /variants/{id}/decision, /cases/{id}/report, /phenotypes for the picker.
Scoring moved under the case and now answers 503 with the reason when no model registry is
reachable, instead of a 500.

Verified end to end on a simulated proband (scripts/make-demo-case.sh: real GIAB HG002
background + one real ClinVar 2-star pathogenic NF2 variant). 13 variants called -> 1 coding
candidate, and the planted variant ranks first at 0.80 on phenotype 1.00, rarity 1.00 and
consequence 1.00, with ClinVar agreeing afterwards.

Tests: api 75, ml 18, loader 16, web 27; ruff, mypy, svelte-check, terraform validate, both
kustomize overlays and the Nextflow stub run all clean.

api/tests/test_cloudrun.py

@@ -26,9 +26,9 @@ class FakeJobsClient:
         return self.result
 
 
-async def new_sample(client: AsyncClient) -> str:
+async def new_case(client: AsyncClient) -> str:
     r = await client.post(
-        "/api/samples",
+        "/api/cases",
         json={"name": f"s-{uuid.uuid4()}", "vcf_uri": "gs://bucket/x.vcf.gz", "assembly": "GRCh37"},
     )
     assert r.status_code == 201, r.text
@@ -49,9 +49,9 @@ async def test_annotate_executes_the_job_with_pipeline_arguments(
 ) -> None:
     jobs = FakeJobsClient(FakeOperation("projects/p/locations/l/executions/rarelens-nextflow-abc12"))
     monkeypatch.setattr(events, "_jobs_client", lambda: jobs)
-    sample_id = await new_sample(client)
+    case_id = await new_case(client)
 
-    r = await client.post(f"/api/samples/{sample_id}/annotate")
+    r = await client.post(f"/api/cases/{case_id}/annotate")
     assert r.status_code == 202
     job = r.json()
     assert job["status"] == "running"
@@ -74,9 +74,9 @@ async def test_a_failed_execution_call_marks_the_job_failed(
     monkeypatch.setattr(
         events, "_jobs_client", lambda: FakeJobsClient(RuntimeError("403 permission denied"))
     )
-    sample_id = await new_sample(client)
+    case_id = await new_case(client)
 
-    job = (await client.post(f"/api/samples/{sample_id}/annotate")).json()
+    job = (await client.post(f"/api/cases/{case_id}/annotate")).json()
     assert job["status"] == "failed"
     assert "403 permission denied" in job["log"]
 
@@ -91,7 +91,7 @@ async def test_cloud_run_job_takes_precedence_over_pubsub(
     monkeypatch.setattr(
         events, "_publisher", lambda: pytest.fail("Pub/Sub must not be used in the serverless track")
     )
-    sample_id = await new_sample(client)
+    case_id = await new_case(client)
 
-    assert (await client.post(f"/api/samples/{sample_id}/annotate")).json()["status"] == "running"
+    assert (await client.post(f"/api/cases/{case_id}/annotate")).json()["status"] == "running"
     assert len(jobs.requests) == 1