feat: add keyboard navigation to member details and fix attendance count

- Users can now navigate between members in the details popup using Up/Down arrows.
- Fixed 0 attendance count in member popup by preserving count in reconciliation.
- Updated uv.lock following dependency changes.

Co-authored-by: Antigravity <antigravity@google.com>

scripts/match_payments.py

@@ -286,7 +286,7 @@ def reconcile(
     """
     member_names = [name for name, _, _ in members]
     member_tiers = {name: tier for name, tier, _ in members}
-    member_fees = {name: {m: fee for m, (fee, _) in fees.items()} for name, _, fees in members}
+    member_fees = {name: fees for name, _, fees in members}
 
     # Initialize ledger
     ledger: dict[str, dict[str, dict]] = {}