feat(rules): show what an apply run changed, and which rule ran

Apply History listed only counts - '13 matches · 13 transactions' - which reads
identically whether the run renamed a merchant or split every transaction with
another participant. Revert is destructive, so that is not enough to decide on.

Two additions. Migration 0017 records rule_id, rule_name and source on each run:
rule_name is denormalised so history stays readable after a rule is edited or
deleted, and there is no FK so deleting a rule cannot cascade away the audit
trail. Both write paths now populate it - the condition-matched run and the
selection-based quick action.

And rows expand to show the run's snapshot set against current values: which
transactions were touched and what changed on each. Rows changed by something
else since the run are called out, because reverting restores the pre-run value
and would discard that later edit.

Runs recorded before this show 'Unknown rule' - the rule they came from is not
recoverable.

prisma/migrations/0017_rule_run_provenance/migration.sql

@@ -0,0 +1,28 @@
+-- Record which rule a run came from.
+--
+-- rule_apply_runs stored only counts ("13 matches · 13 transactions"), which is
+-- not enough to decide whether to revert: you cannot tell a merchant rename from
+-- a 50/50 split of your entire history. The snapshot column already holds the
+-- before-state, but nothing said what was applied or why.
+--
+-- rule_name is denormalised deliberately. A run must stay readable after the
+-- rule it came from is edited or deleted -- the history is a record of what
+-- happened, not a pointer to what the rule says today.
+
+ALTER TABLE rule_apply_runs
+  ADD COLUMN IF NOT EXISTS rule_id   INTEGER,
+  ADD COLUMN IF NOT EXISTS rule_name TEXT,
+  -- 'all' = bulk run over every enabled rule; 'rule' = one rule by conditions;
+  -- 'selection' = one rule against hand-picked transactions (preview → apply).
+  ADD COLUMN IF NOT EXISTS source    TEXT;
+
+ALTER TABLE rule_apply_runs DROP CONSTRAINT IF EXISTS rule_apply_runs_source_check;
+ALTER TABLE rule_apply_runs ADD CONSTRAINT rule_apply_runs_source_check
+  CHECK (source IS NULL OR source IN ('all', 'rule', 'selection'));
+
+-- No FK to rules: deleting a rule must not cascade away the audit trail.
+CREATE INDEX IF NOT EXISTS idx_rule_apply_runs_rule
+  ON rule_apply_runs (rule_id) WHERE rule_id IS NOT NULL;
+
+-- Existing rows stay NULL. There is no way to recover which rule they ran;
+-- the UI shows them as "unknown rule" rather than guessing.