Grid/contacts unification step 1: real contact_id link + grid as front door (v0.1.0:52)

Structural fix for the duplicate-people class of bug: instead of matching a grid
contact "pill" to a contacts row heuristically by name/email (which drifted and
caused the 1406 double-count), link them by id.

Backend:
- Migration 0004: fundraising_contacts.contact_id (additive, nullable, logical FK
  to contacts(id)) + index. Paired down migration.
- sync_fundraising_relational now stores the id that _upsert_contact_from_fundraising
  already returns, so every grid contact carries its contacts-table id.
- _backfill_grid_contact_ids: one-time, idempotent backfill on startup (re-runs the
  grid sync once if any row lacks contact_id), so existing data links immediately.
- entity_resolution: grid pass prefers the explicit contact_id link (match_kind
  'grid_link') over heuristic email / name+investor, guarded by a PRAGMA check so
  older DBs without the column still work.

Frontend:
- Fundraising grid "+ Row" -> "+ Investor" (clear, single investor entry point).
- Contacts page: the "+ Add Contact" trigger is replaced by a pointer to the grid;
  the page is now a read/search/edit view (ContactDetailPanel still edits all
  fields). New people are added from the grid. No contact data is removed.

Tests: backend/ingest/test_entity_resolution.py extended (explicit-link case, 11/11)
and a new backend/test_grid_contact_link.py integration test (init_db applies 0004,
sync populates contact_id to the right contact, re-sync is idempotent). py_compile +
frontend html.parser clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/ingest/test_entity_resolution.py

@@ -57,7 +57,7 @@ CREATE TABLE contacts (
 );
 CREATE TABLE organizations (id TEXT PRIMARY KEY, name TEXT, email TEXT);
 CREATE TABLE fundraising_investors (id TEXT PRIMARY KEY, investor_name TEXT);
-CREATE TABLE fundraising_contacts (id TEXT PRIMARY KEY, full_name TEXT, email TEXT, investor_id TEXT);
+CREATE TABLE fundraising_contacts (id TEXT PRIMARY KEY, full_name TEXT, email TEXT, investor_id TEXT, contact_id TEXT);
 CREATE TABLE lp_profiles (id TEXT PRIMARY KEY, contact_id TEXT, deleted_at TEXT);
 """
 
@@ -72,15 +72,17 @@ def seed(db):
         ("c1", "Alice", "Anderson", "alice@x.com", None),   # email, no org
         ("c2", "Bob", "Brown", None, None),                  # no email, no org
         ("c3", "Dave", "Davis", None, "o1"),                 # no email, org = Acme
+        ("c4", "Frank", "Foster", "frank@x.com", None),      # target of an explicit id link
     ])
     c.executemany("INSERT INTO fundraising_investors (id, investor_name) VALUES (?,?)", [
         ("i_acme", "Acme Capital"), ("i_beta", "Beta Family Office"),
     ])
-    c.executemany("INSERT INTO fundraising_contacts (id, full_name, email, investor_id) VALUES (?,?,?,?)", [
-        ("g_alice", "Alice Anderson", "alice@x.com", "i_beta"),  # -> email match to c1
-        ("g_dave", "Dave Davis", None, "i_acme"),                # -> name+investor match to c3
-        ("g_bob", "Bob Brown", None, "i_beta"),                  # -> MISS (c2 has no org) -> mint NOTHING
-        ("g_carol", "Carol Clark", None, "i_beta"),              # -> MISS (no contact) -> mint NOTHING
+    c.executemany("INSERT INTO fundraising_contacts (id, full_name, email, investor_id, contact_id) VALUES (?,?,?,?,?)", [
+        ("g_alice", "Alice Anderson", "alice@x.com", "i_beta", None),  # -> email match to c1
+        ("g_dave", "Dave Davis", None, "i_acme", None),                # -> name+investor match to c3
+        ("g_bob", "Bob Brown", None, "i_beta", None),                  # -> MISS (c2 has no org) -> mint NOTHING
+        ("g_carol", "Carol Clark", None, "i_beta", None),              # -> MISS (no contact) -> mint NOTHING
+        ("g_link", "Totally Mismatched", None, "i_beta", "c4"),        # -> explicit contact_id link wins over name/inv
     ])
     # Stale grid-only "twin" (person, only a fundraising_contacts link, no enrichment) -> prune
     c.execute("INSERT INTO canonical_entities (id, entity_kind, display_name, source) VALUES "
@@ -150,13 +152,15 @@ def main():
     counts1, _ = er.run(db)
     print(f"Run 1 counts: {counts1}")
 
-    # 3 contacts; grid rows either link back (g_alice, g_dave) or are skipped
-    # (g_bob, g_carol). NO grid row mints a person -> count stays 3, not 5-7.
-    check(resolved_persons(db) == 3, f"resolved persons == 3 (got {resolved_persons(db)}); old double-count would be 5-7")
+    # 4 contacts; grid rows either link back (g_alice email, g_dave name+inv,
+    # g_link explicit id) or are skipped (g_bob, g_carol). NO grid row mints a
+    # person -> count stays 4, not 7-9.
+    check(resolved_persons(db) == 4, f"resolved persons == 4 (got {resolved_persons(db)}); old double-count would be 7-9")
     check(minted_from_grid(db) == 0, f"zero persons minted from grid rows (got {minted_from_grid(db)})")
 
     mk = grid_match_kinds(db)
     check(mk.get("grid_assoc", 0) == 2, f"two grid contacts matched back via grid_assoc (got {mk.get('grid_assoc',0)})")
+    check(mk.get("grid_link", 0) == 1, f"one grid contact linked via explicit contact_id (grid_link==1, got {mk.get('grid_link',0)})")
 
     # Targeted cleanup: stale grid-only twin + superseded 'lp' row tombstoned...
     check(deleted_at(db, "per_TWIN") is not None, "stale grid-only twin 'per_TWIN' tombstoned")
@@ -174,7 +178,7 @@ def main():
     counts2, _ = er.run(db)
     print(f"Run 2 counts: {counts2}")
     check(deleted_at(db, alice) is None, "re-emitted contact-person is UN-tombstoned (no permanent burial)")
-    check(resolved_persons(db) == 3, f"resolved persons stable at 3 on re-run (got {resolved_persons(db)})")
+    check(resolved_persons(db) == 4, f"resolved persons stable at 4 on re-run (got {resolved_persons(db)})")
     check(counts2.get("pruned_stale", 0) == 0, f"nothing re-pruned on idempotent re-run (got {counts2.get('pruned_stale')})")
 
     print()