feat(analysis): fetch real MP metadata, fix anchor axis for party-level actors

- fetch_mp_metadata: use real OData URL with pagination (1200 records, 5 pages)
  uses Fractie.Afkorting not NaamNL for abbreviation matching
  skips Verwijderd=true records
- upsert_mp_metadata: keep most recent membership (prefer active over ended,
  then higher Van date) so current party affiliations are not overwritten by historical
- compute_anchor_axis: anchor directly on party-level SVD entities (GroenLinks-PvdA etc)
  before falling back to mp_metadata individual MP lookup
- test_fetch_mp_metadata: fix mock for timeout kwarg + pagination + Afkorting field
- Generated anchor axis HTML for 2025-Q2 through 2026-Q1 in outputs/

analysis/political_axis.py

@@ -87,22 +87,24 @@ def compute_anchor_axis(
     if not mp_vecs:
         return {}
 
-    # Load party affiliation for this window from mp_metadata
+    left_set = set(left_parties)
+    right_set = set(right_parties)
+
+    # 1. Party-level actors whose entity_id IS a party name (e.g. "GroenLinks-PvdA")
+    left_vecs = [mp_vecs[p] for p in left_set if p in mp_vecs]
+    right_vecs = [mp_vecs[p] for p in right_set if p in mp_vecs]
+
+    # 2. Individual MPs via mp_metadata party affiliation
     conn = duckdb.connect(db_path)
     rows = conn.execute("SELECT mp_name, party FROM mp_metadata").fetchall()
     conn.close()
-    party_of = {mp: party for mp, party in rows}
-
-    left_vecs = [
-        mp_vecs[mp]
-        for mp, party in party_of.items()
-        if party in left_parties and mp in mp_vecs
-    ]
-    right_vecs = [
-        mp_vecs[mp]
-        for mp, party in party_of.items()
-        if party in right_parties and mp in mp_vecs
-    ]
+    for mp_name, party in rows:
+        if mp_name not in mp_vecs:
+            continue
+        if party in left_set and mp_name not in left_set:
+            left_vecs.append(mp_vecs[mp_name])
+        elif party in right_set and mp_name not in right_set:
+            right_vecs.append(mp_vecs[mp_name])
 
     if not left_vecs or not right_vecs:
         _logger.warning(