feat(pipeline): implement parliamentary embedding pipeline MVP

- Add 4 migration files: mp_votes, mp_metadata, svd_vectors, fused_embeddings
- Extend database.py with 5 new helper methods and table init
- Add pipeline/ package: extract_mp_votes, fetch_mp_metadata, text_pipeline,
  svd_pipeline (with Procrustes alignment), fusion
- Add full test suite (17 tests) covering all pipeline modules and migrations
- Fix Procrustes alignment bug: scipy scale is a norm value, not a multiplier
- Fix DuckDB date type handling in test assertions (datetime.date vs string)
- Remove duckdb.py shim; tests now run against real duckdb + scipy via uv

Ref: thoughts/shared/plans/2026-03-21-parliamentary-embedding-pipeline-plan.md

tests/fixtures/__init__.py

@@ -0,0 +1 @@
+"""Fixtures package for tests."""

tests/fixtures/sample_voting_results.json

@@ -0,0 +1,40 @@
+[
+  {
+    "motion_id": 1,
+    "date": "2024-01-15",
+    "voting_results": {
+      "VVD": "voor",
+      "PvdA": "tegen",
+      "CDA": "voor",
+      "D66": "voor",
+      "Wilders, G.": "voor",
+      "Yesilgöz-Zegerius, D.": "voor",
+      "Jetten, R.A.A.": "voor"
+    }
+  },
+  {
+    "motion_id": 2,
+    "date": "2024-02-10",
+    "voting_results": {
+      "VVD": "tegen",
+      "PvdA": "voor",
+      "CDA": "afwezig",
+      "D66": "voor",
+      "Wilders, G.": "tegen",
+      "Yesilgöz-Zegerius, D.": "tegen",
+      "Ploumen, L.J.": "voor"
+    }
+  },
+  {
+    "motion_id": 3,
+    "date": "2024-03-05",
+    "voting_results": {
+      "VVD": "voor",
+      "SP": "tegen",
+      "GroenLinks": "voor",
+      "PVV": "voor",
+      "Van der Plas, C.": "voor",
+      "Klever, N.C.": "voor"
+    }
+  }
+]