feat(infrastructure): implement SQLite persistence layer for calendar domain

Add infrastructure layer with SQLite repositories for
calendars, events, and recurring events. Implements the repository
pattern with proper domain/infrastructure separation.

- Add CalendarModel, EventModel, RecurrenceModel, and RecurrenceExceptionModel
  for database persistence
- Implement SqliteCalendarRepository with CRUD operations
- Implement SqliteEventRepository with calendar filtering and time range queries
- Implement SqliteRecurringEventRepository with exception handling and transactions
- Add bidirectional mappers between domain entities and persistence models
- Use sqlx query_as for type-safe database queries with FromRow derivation
- Support upsert operations for all entities using ON CONFLICT clauses

1 files changed, 53 insertions, 0 deletions

diff --git a/src/infrastructure/persistence/models.rs b/src/infrastructure/persistence/models.rs
new file mode 100644
index 0000000..dc39e94
--- /dev/null
+++ b/src/infrastructure/persistence/models.rs
@@ -0,0 +1,53 @@
+use sqlx::FromRow;
+
+#[derive(Debug, FromRow)]
+pub struct CalendarModel {
+    pub id: String,
+    pub name: String,
+    pub description: Option<String>,
+    pub is_archived: i64,
+    pub created_at: String,
+    pub updated_at: String,
+}
+
+#[derive(Debug, FromRow)]
+pub struct EventModel {
+    pub id: String,
+    pub calendar_id: String,
+    pub title: String,
+    pub description: Option<String>,
+    pub starts_at: String,
+    pub ends_at: String,
+    pub color: i64,
+    pub is_all_day: i64,
+    pub is_cancelled: i64,
+    pub created_at: String,
+    pub updated_at: String,
+}
+
+#[derive(Debug, FromRow)]
+pub struct RecurrenceModel {
+    pub id: String,
+    pub calendar_id: String,
+    pub title: String,
+    pub description: Option<String>,
+    pub starts_at: String,
+    pub ends_at: String,
+    pub frequency: String,
+    pub interval: i64,
+    pub until: Option<String>,
+    pub color: i64,
+    pub is_all_day: i64,
+    pub is_cancelled: i64,
+    pub created_at: String,
+    pub updated_at: String,
+}
+
+#[derive(Debug, FromRow)]
+pub struct RecurrenceExceptionModel {
+    pub recurrence_id: String,
+    pub original_starts_at: String,
+    pub new_starts_at: Option<String>,
+    pub new_ends_at: Option<String>,
+    pub is_cancelled: i64,
+}