feat(ownership): complete ownership intelligence module

Sprints 0-8: Types, schema, KSEI parser, entity resolution, DB CRUD,
Bing API client, import pipeline, query commands, graph traversal,
changes diff, entity resolution CLI, FTS5 search.

- KSEI PDF parser (mutool stext + quick-xml, 99.2% accuracy)
- 7 query commands: ticker, entity, search, cross-holders, concentration, flow, releases
- Ownership graph with recursive CTE (ASCII tree + Graphviz DOT)
- Release diff/changes between KSEI snapshots
- Entity resolution CLI: unresolved, map, merge
- FTS5 trigram search on entity names
- Feature-gated under 'ownership' (default-on)
- 82 tests passing

tests/fixtures/bing_buyers_bbca.json

@@ -0,0 +1,47 @@
+[
+  {
+    "investorName": "Norges Bank Investment Management",
+    "investorType": "Government / Sovereign Wealth",
+    "sharesHeld": 278330000.0,
+    "sharesChanged": 3200000.0,
+    "percentageOfSharesOutstanding": 1.13,
+    "value": 275196270000.0,
+    "reportDate": "2024-12-31"
+  },
+  {
+    "investorName": "Dimensional Fund Advisors LP",
+    "investorType": "Institutional",
+    "sharesHeld": 156920000.0,
+    "sharesChanged": 14750000.0,
+    "percentageOfSharesOutstanding": 0.64,
+    "value": 155110680000.0,
+    "reportDate": "2024-12-31"
+  },
+  {
+    "investorName": "Baillie Gifford & Co",
+    "investorType": "Institutional",
+    "sharesHeld": 132450000.0,
+    "sharesChanged": 11200000.0,
+    "percentageOfSharesOutstanding": 0.54,
+    "value": 130965450000.0,
+    "reportDate": "2024-12-31"
+  },
+  {
+    "investorName": "BlackRock Inc",
+    "investorType": "Institutional",
+    "sharesHeld": 498112750.0,
+    "sharesChanged": 5600000.0,
+    "percentageOfSharesOutstanding": 2.02,
+    "value": 492523521250.0,
+    "reportDate": "2024-12-31"
+  },
+  {
+    "investorName": "Fidelity Management & Research",
+    "investorType": "Institutional",
+    "sharesHeld": 89340000.0,
+    "sharesChanged": 4100000.0,
+    "percentageOfSharesOutstanding": 0.36,
+    "value": 88346060000.0,
+    "reportDate": "2024-12-31"
+  }
+]