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/api/src/routes/channels/schedule.rs

@@ -0,0 +1,56 @@
+use axum::{
+    Json,
+    extract::{Path, State},
+    http::StatusCode,
+    response::IntoResponse,
+};
+use chrono::Utc;
+use uuid::Uuid;
+
+use domain::DomainError;
+
+use crate::{
+    dto::ScheduleResponse,
+    error::ApiError,
+    extractors::CurrentUser,
+    state::AppState,
+};
+
+use super::require_owner;
+
+/// Trigger 48-hour schedule generation for a channel, starting from now.
+/// Replaces any existing schedule for the same window.
+pub(super) async fn generate_schedule(
+    State(state): State<AppState>,
+    CurrentUser(user): CurrentUser,
+    Path(channel_id): Path<Uuid>,
+) -> Result<impl IntoResponse, ApiError> {
+    let channel = state.channel_service.find_by_id(channel_id).await?;
+    require_owner(&channel, user.id)?;
+
+    let schedule = state
+        .schedule_engine
+        .generate_schedule(channel_id, Utc::now())
+        .await?;
+
+    Ok((StatusCode::CREATED, Json(ScheduleResponse::from(schedule))))
+}
+
+/// Return the currently active 48-hour schedule for a channel.
+/// 404 if no schedule has been generated yet — call POST /:id/schedule first.
+pub(super) async fn get_active_schedule(
+    State(state): State<AppState>,
+    CurrentUser(user): CurrentUser,
+    Path(channel_id): Path<Uuid>,
+) -> Result<impl IntoResponse, ApiError> {
+    let channel = state.channel_service.find_by_id(channel_id).await?;
+    require_owner(&channel, user.id)?;
+
+    let schedule = state
+        .schedule_engine
+        .get_active_schedule(channel_id, Utc::now())
+        .await?
+        .ok_or(DomainError::NoActiveSchedule(channel_id))?;
+
+    Ok(Json(ScheduleResponse::from(schedule)))
+}