fix(balance): pre-seed balance_starter_proposed pref for new profiles (S1)

Before this commit, a brand-new profile briefly showed the
StarterAccountsModal even though the 4 starter accounts were already
seeded — the modal rendered 4 collision rows with no actionable choice
before being dismissed. Pre-seeding the pref in consolidated_schema.sql
suppresses the modal on first /balance visit for new profiles entirely.

Existing profiles already running the app are unaffected: they handle
the modal once on their first /balance visit (the pref-write happens on
dismiss). No migration is needed for them.

Suggestion S1 from PR #185 review (#187).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src-tauri/src/database/consolidated_schema.sql

@@ -288,6 +288,12 @@ INSERT OR IGNORE INTO user_preferences (key, value) VALUES ('theme', 'light');
 INSERT OR IGNORE INTO user_preferences (key, value) VALUES ('currency', 'EUR');
 INSERT OR IGNORE INTO user_preferences (key, value) VALUES ('date_format', 'DD/MM/YYYY');
 INSERT OR REPLACE INTO user_preferences (key, value) VALUES ('categories_schema_version', 'v1');
+-- Suppress StarterAccountsModal on first /balance visit for new profiles
+-- (Issue #179). The 4 starter accounts are already seeded above, so the
+-- modal would only show 4 collision rows with no actionable choice. Pre-
+-- writing the pref skips that briefly-empty UX entirely. Suggestion S1
+-- from PR #185 review (#187).
+INSERT OR IGNORE INTO user_preferences (key, value) VALUES ('balance_starter_proposed', '{"shown_at":"seed","accepted":[]}');
 
 -- ============================================================================
 -- Seed v1 — IPC Statistique Canada-aligned, 3 levels, Canada/Québec

src/pages/BalancePage.tsx

@@ -58,10 +58,9 @@ export default function BalancePage() {
 
   // Issue #179 — one-shot starter-accounts modal for existing profiles. The
   // pref `balance_starter_proposed` is written once (confirmed or dismissed),
-  // so the modal never re-appears. New profiles get the 4 starters seeded
-  // directly via consolidated_schema.sql and never hit this branch (the
-  // first /balance visit will write the pref with accepted=[] silently
-  // since collisions match all 4).
+  // so the modal never re-appears. New profiles get both the 4 starters AND
+  // the pref pre-seeded via consolidated_schema.sql, so they never hit this
+  // branch at all (S1 fix from #187).
   const [showStarterModal, setShowStarterModal] = useState(false);
   useEffect(() => {
     let cancelled = false;