fix: overhaul the platform skeleton, add a serverless deployment track

An end-to-end audit found the repo could not build, test or run as shipped. This
fixes every finding, then adds a Cloud Run track so the demo costs about £1/month
idle instead of ~£150.

CI (red on its first run)
- api: setuptools could not build the package (flat layout with app/ and alembic/)
- web: missing @types/node; `vitest run` exited 1 with no test files
- pipeline: the stub run needed a gitignored VCF, and no process had a stub block
- ruff pinned, mypy configured, DB tests on real Postgres (pgserver locally, service in CI)

ML serving (scores were meaningless)
- the registered model now carries its own feature engineering and returns predict_proba,
  so serving sends raw columns and cannot drift from training
- resolve by registry alias (stages are deprecated in MLflow 3) and record the real
  version; re-scoring upserts instead of failing on the unique constraint
- ClinVar labels parsed from VEP's lowercase terms

Pipeline
- exact ref/alt recovered from a CHROM_POS_REF_ALT VCF ID; loading is idempotent
- job status reaches running/failed/succeeded, so the UI stops polling dead jobs
- DATABASE_URL travels in the environment or a Nextflow secret, never on a command line
- VEP cache and plugins staged as inputs; the gcp profile runs tasks on Google Batch

Deployment
- the API serves /api (matching the ingress); the web app reads its API URL at runtime
- migrations run in an init container under a Postgres advisory lock
- terraform: custom VPC shared with Batch, private Cloud SQL, API enablement, Workload
  Identity bindings, Secret Manager, deletion protection
- serverless track, now the default: Cloud Run services scaling to zero, a Cloud Run job
  for the Nextflow driver, and Neon or Cloud SQL behind one DATABASE_URL secret. GKE and
  Argo remain, behind -var deploy_kubernetes=true. See docs/cloud.md.

Correctness and security
- 409 on duplicate sample names, 422 on bad paging, natural chromosome ordering, wider
  VEP text columns, enum dropped on downgrade, the sample's assembly actually used
- vcf_uri restricted to gs:// objects or files under the data root, blocking option injection
- CORS restricted to configured origins; `make down` no longer deletes volumes

Data
- docs/data.md records the peer-reviewed, openly licensed sources (GIAB HG002, ClinVar,
  gnomAD) with citations and an honest evaluation plan; `make data` fetches a chr22 slice

Verified: api 50 tests, ml 18, loader 16, web 12; ruff, mypy, svelte-check, terraform
validate and both kustomize overlays clean.

api/app/db.py

@@ -1,13 +1,33 @@
 from collections.abc import AsyncIterator
+from typing import Annotated
 
+from fastapi import Depends
+from sqlalchemy.engine import make_url
 from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
 
 from app.config import settings
 
-engine = create_async_engine(settings.database_url, pool_pre_ping=True)
+
+def normalize_async_url(url: str) -> str:
+    """Translate libpq's `sslmode=` into the `ssl=` asyncpg understands.
+
+    Hosted Postgres (Neon, Supabase) hands out sslmode= URLs, which asyncpg rejects outright.
+    """
+    parsed = make_url(url)
+    if "asyncpg" not in parsed.drivername or "sslmode" not in parsed.query:
+        return url
+    query = dict(parsed.query)
+    query["ssl"] = query.pop("sslmode")
+    return parsed.set(query=query).render_as_string(hide_password=False)
+
+
+engine = create_async_engine(normalize_async_url(settings.database_url), pool_pre_ping=True)
 SessionLocal = async_sessionmaker(engine, expire_on_commit=False)
 
 
 async def get_session() -> AsyncIterator[AsyncSession]:
     async with SessionLocal() as session:
         yield session
+
+
+SessionDep = Annotated[AsyncSession, Depends(get_session)]