Implement automatic reminder engine with admin and company UI.

Add schema v6, read-only scan rules for unsubmitted flows, gaps and pending reviews, deduplicated delivery with append-only event history, daily scan thread, and full API/frontend integration with 18 new tests.

Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: multica-agent <github@multica.ai>

src/bank_importer/db.py

@@ -569,6 +569,78 @@ MIGRATIONS: tuple[Migration, ...] = (
         ALTER TABLE import_batches DROP COLUMN upload_bank_account_id;
         """,
     ),
+    Migration(
+        version=6,
+        name="0006_reminders",
+        up="""
+        CREATE TABLE reminder_settings (
+            key TEXT PRIMARY KEY,
+            value TEXT NOT NULL,
+            updated_at TEXT NOT NULL
+        );
+
+        INSERT INTO reminder_settings (key, value, updated_at) VALUES
+            ('monthly_start_day', '5', datetime('now')),
+            ('gap_days', '5', datetime('now')),
+            ('scan_time', '08:00', datetime('now'));
+
+        CREATE TABLE reminders (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            company_id INTEGER NOT NULL REFERENCES companies (id),
+            rule_key TEXT NOT NULL CHECK (rule_key IN (
+                'unsubmitted', 'gap', 'pending_review', 'manual'
+            )),
+            dedupe_key TEXT NOT NULL UNIQUE,
+            rule_params TEXT NOT NULL DEFAULT '{}',
+            title TEXT NOT NULL,
+            content TEXT NOT NULL,
+            deadline TEXT,
+            source TEXT NOT NULL CHECK (source IN ('auto', 'manual')),
+            status TEXT NOT NULL DEFAULT 'open'
+                CHECK (status IN ('open', 'acknowledged', 'resolved')),
+            send_count INTEGER NOT NULL DEFAULT 0,
+            first_sent_at TEXT,
+            last_sent_at TEXT,
+            created_by TEXT NOT NULL,
+            created_at TEXT NOT NULL,
+            action_link TEXT
+        );
+
+        CREATE INDEX idx_reminders_company ON reminders (company_id);
+        CREATE INDEX idx_reminders_status ON reminders (status);
+
+        CREATE TABLE reminder_events (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            reminder_id INTEGER NOT NULL REFERENCES reminders (id),
+            event_type TEXT NOT NULL CHECK (event_type IN (
+                'sent', 'acknowledged', 'resolved', 'escalated'
+            )),
+            actor TEXT NOT NULL,
+            detail TEXT,
+            created_at TEXT NOT NULL
+        );
+
+        CREATE INDEX idx_reminder_events_reminder ON reminder_events (reminder_id);
+
+        CREATE TRIGGER reminder_events_no_update BEFORE UPDATE ON reminder_events
+        BEGIN SELECT RAISE (ABORT, 'reminder_events rows are append-only'); END;
+        CREATE TRIGGER reminder_events_no_delete BEFORE DELETE ON reminder_events
+        BEGIN SELECT RAISE (ABORT, 'reminder_events rows are append-only'); END;
+        CREATE TRIGGER reminders_no_delete BEFORE DELETE ON reminders
+        BEGIN SELECT RAISE (ABORT, 'reminders rows are immutable history'); END;
+        """,
+        down="""
+        DROP TRIGGER IF EXISTS reminders_no_delete;
+        DROP TRIGGER IF EXISTS reminder_events_no_delete;
+        DROP TRIGGER IF EXISTS reminder_events_no_update;
+        DROP INDEX IF EXISTS idx_reminder_events_reminder;
+        DROP TABLE IF EXISTS reminder_events;
+        DROP INDEX IF EXISTS idx_reminders_status;
+        DROP INDEX IF EXISTS idx_reminders_company;
+        DROP TABLE IF EXISTS reminders;
+        DROP TABLE IF EXISTS reminder_settings;
+        """,
+    ),
 )