split scheduling into scan + process windows, move controls to settings page

the old one-window scheduler gated only the job queue. now the scan loop and
the processing queue have independent windows — useful when the container
runs as an always-on service and we only want to hammer jellyfin + ffmpeg
at night.

config keys renamed from schedule_* to scan_schedule_* / process_schedule_*,
plus the existing job_sleep_seconds. scheduler.ts exposes parallel helpers
(isInScanWindow / isInProcessWindow, waitForScanWindow / waitForProcessWindow)
so each caller picks its window without cross-contamination.

scan.ts checks the scan window between items and emits paused/resumed sse.
execute.ts keeps its per-job pause + sleep-between-jobs but now on the
process window. /api/execute/scheduler moved to /api/settings/schedule.

frontend: ScheduleControls popup deleted from the pipeline header, replaced
with a plain Start queue button. settings page grows a Schedule section with
both windows and the job sleep input.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/api/settings.ts

@@ -2,6 +2,7 @@ import { Hono } from "hono";
 import { getAllConfig, getDb, getEnvLockedKeys, setConfig } from "../db/index";
 import { getUsers, testConnection as testJellyfin } from "../services/jellyfin";
 import { testConnection as testRadarr } from "../services/radarr";
+import { getScheduleConfig, type ScheduleConfig, updateScheduleConfig } from "../services/scheduler";
 import { testConnection as testSonarr } from "../services/sonarr";
 
 const app = new Hono();
@@ -96,6 +97,16 @@ app.post("/audio-languages", async (c) => {
 	return c.json({ ok: true });
 });
 
+app.get("/schedule", (c) => {
+	return c.json(getScheduleConfig());
+});
+
+app.patch("/schedule", async (c) => {
+	const body = await c.req.json<Partial<ScheduleConfig>>();
+	updateScheduleConfig(body);
+	return c.json(getScheduleConfig());
+});
+
 app.post("/clear-scan", (c) => {
 	const db = getDb();
 	// Delete children first to avoid slow cascade deletes