clean(presentation): strip comments, kill dead code, extract constants

- remove all doc/inline comments
- delete unused ApiError variants (AuthRequired, NotImplemented) and helpers (internal, not_implemented)
- prefix lifetime-only AppState fields with _ to suppress dead_code warning
- extract magic numbers: TICK_INTERVAL_SECS, EXPIRY_THRESHOLD_HOURS, POLL_INTERVAL_SECS, EVENT_BUS_CAPACITY, DEFAULT_ACTIVITY_LIMIT, DEFAULT_SEARCH_LIMIT, etc
- replace inline serde_json::json! in sync_status with typed SyncStatusEntry
- fix mid-file import in schedule handler
- fix extractors: strip_prefix instead of magic offset 6
- fix unreachable pattern in wire_repositories with cfg guard
- use eq_ignore_ascii_case for content-type header check

crates/presentation/src/handlers/schedule.rs

@@ -1,8 +1,7 @@
-//! Schedule, broadcast, and stream handlers.
-
 use axum::Json;
 use axum::extract::{Path, State};
 use axum::http::StatusCode;
+use axum::response::IntoResponse;
 
 use api_types::{
     CurrentBroadcastResponse, ScheduleHistoryEntry, ScheduleResponse, SlotResponse,
@@ -16,7 +15,6 @@ use crate::errors::ApiError;
 use crate::extractors::CurrentUser;
 use crate::state::AppState;
 
-/// POST /channels/:id/schedule — generate a new schedule
 pub async fn generate_schedule(
     State(state): State<AppState>,
     CurrentUser(_user): CurrentUser,
@@ -27,7 +25,6 @@ pub async fn generate_schedule(
     Ok(Json(ScheduleResponse::from(schedule)))
 }
 
-/// GET /channels/:id/schedule — get the active schedule
 pub async fn get_active_schedule(
     State(state): State<AppState>,
     CurrentUser(_user): CurrentUser,
@@ -40,9 +37,6 @@ pub async fn get_active_schedule(
     }
 }
 
-use axum::response::IntoResponse;
-
-/// GET /channels/:id/now — what's currently playing
 pub async fn get_current_broadcast(
     State(state): State<AppState>,
     Path(id): Path<uuid::Uuid>,
@@ -51,7 +45,6 @@ pub async fn get_current_broadcast(
     match application::schedule::get_current_broadcast::execute(&state.schedule_deps, query).await?
     {
         Some(broadcast) => {
-            // Look up the channel to resolve block access mode
             let channel_query = application::channels::GetChannelQuery { channel_id: id };
             let channel = application::channels::get::execute(&state.channel_query_deps, channel_query).await?;
 
@@ -73,7 +66,6 @@ pub async fn get_current_broadcast(
     }
 }
 
-/// GET /channels/:id/epg — electronic program guide
 pub async fn get_epg(
     State(state): State<AppState>,
     Path(id): Path<uuid::Uuid>,
@@ -83,12 +75,10 @@ pub async fn get_epg(
     Ok(Json(slots.into_iter().map(SlotResponse::from).collect()))
 }
 
-/// GET /channels/:id/stream — redirect to stream URL (307)
 pub async fn get_stream(
     State(state): State<AppState>,
     Path(id): Path<uuid::Uuid>,
 ) -> Result<axum::response::Response, ApiError> {
-    // Find the current broadcast first to get the item ID
     let broadcast_query = GetCurrentBroadcastQuery { channel_id: id };
     let broadcast =
         application::schedule::get_current_broadcast::execute(&state.schedule_deps, broadcast_query)
@@ -113,7 +103,6 @@ pub async fn get_stream(
     }
 }
 
-/// GET /channels/:id/schedule/history — list schedule generations
 pub async fn list_schedule_history(
     State(state): State<AppState>,
     CurrentUser(_user): CurrentUser,