Add event-sourced wallet and transaction tracking system

Wallets table with 7 seeded wallets, events table for three transaction
types (bank_to_exchange, exchange_to_wallet, wallet_to_wallet). Balances
computed from event credits/debits in sats. REST endpoints for CRUD.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

resources/migrations/20260307000000-create-wallets.down.sql

@@ -0,0 +1 @@
+DROP TABLE wallets;

resources/migrations/20260307000000-create-wallets.up.sql

@@ -0,0 +1,9 @@
+CREATE TABLE wallets (
+  id         UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+  name       TEXT NOT NULL UNIQUE,
+  created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+--;;
+INSERT INTO wallets (name) VALUES
+  ('Crypto.Com'), ('Nexo'), ('CoinCorner'), ('Strike'),
+  ('Cold'), ('Coldcard'), ('Nunchuk Multi Sig');

resources/migrations/20260307100000-create-events.down.sql

@@ -0,0 +1 @@
+DROP TABLE events;

resources/migrations/20260307100000-create-events.up.sql

@@ -0,0 +1,17 @@
+CREATE TABLE events (
+  id             BIGSERIAL PRIMARY KEY,
+  event_type     TEXT NOT NULL,
+  occurred_at    TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+  recorded_at    TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+  sats           BIGINT,
+  fee_sats       BIGINT,
+  fiat_amount    NUMERIC(18,2),
+  fiat_currency  TEXT,
+  from_wallet_id UUID REFERENCES wallets(id),
+  to_wallet_id   UUID REFERENCES wallets(id),
+  note           TEXT
+);
+--;;
+CREATE INDEX idx_events_type ON events (event_type);
+--;;
+CREATE INDEX idx_events_occurred ON events (occurred_at);

resources/queries.sql

@@ -65,3 +65,74 @@ SELECT rate_date, eur, dkk, eur_dkk, updated_at FROM currencies ORDER BY rate_da
 -- :name get-currency-rates-by-date :? :1
 -- :doc Get currency rates for a specific date
 SELECT rate_date, eur, dkk, eur_dkk, updated_at FROM currencies WHERE rate_date = :rate-date
+
+-- Wallets -------------------------------------------------------------------
+
+-- :name insert-wallet! :! :n
+-- :doc Insert a new wallet
+INSERT INTO wallets (name) VALUES (:name)
+
+-- :name get-all-wallets :? :*
+-- :doc Get all wallets
+SELECT id, name, created_at FROM wallets ORDER BY name
+
+-- :name get-wallet-by-id :? :1
+-- :doc Get a wallet by ID
+SELECT id, name, created_at FROM wallets WHERE id = :id
+
+-- Events --------------------------------------------------------------------
+
+-- :name insert-event! :! :n
+-- :doc Insert a new event
+INSERT INTO events (event_type, occurred_at, sats, fee_sats, fiat_amount, fiat_currency, from_wallet_id, to_wallet_id, note)
+VALUES (:event-type, :occurred-at, :sats, :fee-sats, :fiat-amount, :fiat-currency, :from-wallet-id, :to-wallet-id, :note)
+
+-- :name get-all-events :? :*
+-- :doc Get all events with wallet names
+SELECT e.id, e.event_type, e.occurred_at, e.recorded_at,
+       e.sats, e.fee_sats, e.fiat_amount, e.fiat_currency,
+       e.from_wallet_id, fw.name AS from_wallet_name,
+       e.to_wallet_id, tw.name AS to_wallet_name,
+       e.note
+FROM events e
+LEFT JOIN wallets fw ON fw.id = e.from_wallet_id
+LEFT JOIN wallets tw ON tw.id = e.to_wallet_id
+ORDER BY e.occurred_at DESC
+
+-- :name get-events-by-type :? :*
+-- :doc Get events filtered by type
+SELECT e.id, e.event_type, e.occurred_at, e.recorded_at,
+       e.sats, e.fee_sats, e.fiat_amount, e.fiat_currency,
+       e.from_wallet_id, fw.name AS from_wallet_name,
+       e.to_wallet_id, tw.name AS to_wallet_name,
+       e.note
+FROM events e
+LEFT JOIN wallets fw ON fw.id = e.from_wallet_id
+LEFT JOIN wallets tw ON tw.id = e.to_wallet_id
+WHERE e.event_type = :event-type
+ORDER BY e.occurred_at DESC
+
+-- :name get-events-by-wallet :? :*
+-- :doc Get events involving a specific wallet
+SELECT e.id, e.event_type, e.occurred_at, e.recorded_at,
+       e.sats, e.fee_sats, e.fiat_amount, e.fiat_currency,
+       e.from_wallet_id, fw.name AS from_wallet_name,
+       e.to_wallet_id, tw.name AS to_wallet_name,
+       e.note
+FROM events e
+LEFT JOIN wallets fw ON fw.id = e.from_wallet_id
+LEFT JOIN wallets tw ON tw.id = e.to_wallet_id
+WHERE e.from_wallet_id = :wallet-id OR e.to_wallet_id = :wallet-id
+ORDER BY e.occurred_at DESC
+
+-- :name get-wallet-balances :? :*
+-- :doc Compute sats balance per wallet from events
+SELECT w.id, w.name,
+  COALESCE(SUM(CASE WHEN e.to_wallet_id = w.id THEN e.sats ELSE 0 END), 0)
+  - COALESCE(SUM(CASE WHEN e.from_wallet_id = w.id THEN e.sats ELSE 0 END), 0)
+  - COALESCE(SUM(CASE WHEN e.from_wallet_id = w.id THEN e.fee_sats ELSE 0 END), 0)
+  AS balance_sats
+FROM wallets w
+LEFT JOIN events e ON e.from_wallet_id = w.id OR e.to_wallet_id = w.id
+GROUP BY w.id, w.name
+ORDER BY w.name