Refactor schedule and user repositories into modular structure

- Moved schedule repository logic into separate modules for SQLite and PostgreSQL implementations.
- Created a mapping module for shared data structures and mapping functions in the schedule repository.
- Added new mapping module for user repository to handle user data transformations.
- Implemented PostgreSQL and SQLite user repository adapters with necessary CRUD operations.
- Added tests for user repository functionality, including saving, finding, and deleting users.

k-tv-backend/infra/src/channel_repository/sqlite.rs

@@ -0,0 +1,100 @@
+use async_trait::async_trait;
+
+use domain::{Channel, ChannelId, ChannelRepository, DomainError, DomainResult, UserId};
+
+use super::mapping::{ChannelRow, SELECT_COLS};
+
+pub struct SqliteChannelRepository {
+    pool: sqlx::SqlitePool,
+}
+
+impl SqliteChannelRepository {
+    pub fn new(pool: sqlx::SqlitePool) -> Self {
+        Self { pool }
+    }
+}
+
+#[async_trait]
+impl ChannelRepository for SqliteChannelRepository {
+    async fn find_by_id(&self, id: ChannelId) -> DomainResult<Option<Channel>> {
+        let sql = format!("SELECT {SELECT_COLS} FROM channels WHERE id = ?");
+        let row: Option<ChannelRow> = sqlx::query_as(&sql)
+            .bind(id.to_string())
+            .fetch_optional(&self.pool)
+            .await
+            .map_err(|e| DomainError::RepositoryError(e.to_string()))?;
+
+        row.map(Channel::try_from).transpose()
+    }
+
+    async fn find_by_owner(&self, owner_id: UserId) -> DomainResult<Vec<Channel>> {
+        let sql = format!(
+            "SELECT {SELECT_COLS} FROM channels WHERE owner_id = ? ORDER BY created_at ASC"
+        );
+        let rows: Vec<ChannelRow> = sqlx::query_as(&sql)
+            .bind(owner_id.to_string())
+            .fetch_all(&self.pool)
+            .await
+            .map_err(|e| DomainError::RepositoryError(e.to_string()))?;
+
+        rows.into_iter().map(Channel::try_from).collect()
+    }
+
+    async fn find_all(&self) -> DomainResult<Vec<Channel>> {
+        let sql = format!("SELECT {SELECT_COLS} FROM channels ORDER BY created_at ASC");
+        let rows: Vec<ChannelRow> = sqlx::query_as(&sql)
+            .fetch_all(&self.pool)
+            .await
+            .map_err(|e| DomainError::RepositoryError(e.to_string()))?;
+
+        rows.into_iter().map(Channel::try_from).collect()
+    }
+
+    async fn save(&self, channel: &Channel) -> DomainResult<()> {
+        let schedule_config = serde_json::to_string(&channel.schedule_config).map_err(|e| {
+            DomainError::RepositoryError(format!("Failed to serialize schedule_config: {}", e))
+        })?;
+        let recycle_policy = serde_json::to_string(&channel.recycle_policy).map_err(|e| {
+            DomainError::RepositoryError(format!("Failed to serialize recycle_policy: {}", e))
+        })?;
+
+        sqlx::query(
+            r#"
+            INSERT INTO channels
+                (id, owner_id, name, description, timezone, schedule_config, recycle_policy, created_at, updated_at)
+            VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)
+            ON CONFLICT(id) DO UPDATE SET
+                name            = excluded.name,
+                description     = excluded.description,
+                timezone        = excluded.timezone,
+                schedule_config = excluded.schedule_config,
+                recycle_policy  = excluded.recycle_policy,
+                updated_at      = excluded.updated_at
+            "#,
+        )
+        .bind(channel.id.to_string())
+        .bind(channel.owner_id.to_string())
+        .bind(&channel.name)
+        .bind(&channel.description)
+        .bind(&channel.timezone)
+        .bind(&schedule_config)
+        .bind(&recycle_policy)
+        .bind(channel.created_at.to_rfc3339())
+        .bind(channel.updated_at.to_rfc3339())
+        .execute(&self.pool)
+        .await
+        .map_err(|e| DomainError::RepositoryError(e.to_string()))?;
+
+        Ok(())
+    }
+
+    async fn delete(&self, id: ChannelId) -> DomainResult<()> {
+        sqlx::query("DELETE FROM channels WHERE id = ?")
+            .bind(id.to_string())
+            .execute(&self.pool)
+            .await
+            .map_err(|e| DomainError::RepositoryError(e.to_string()))?;
+
+        Ok(())
+    }
+}