Add daily log rotation with monthly folder structure

All log output is now additionally written to daily log files:
  daily-logs/YYYY-MM/YYYY-MM-DD.log (main log)
  daily-logs/YYYY-MM/YYYY-MM-DD-rename.log (rename log)

Automatic cleanup of daily logs older than 30 days. The existing
rd_downloader.log and rename.log continue to work as before.

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

src/main/rename-log.ts

@@ -1,5 +1,6 @@
 import fs from "node:fs";
 import path from "node:path";
+import { writeToDailyRenameLog } from "./daily-log";
 
 type RenameLogLevel = "INFO" | "WARN" | "ERROR";
 
@@ -93,11 +94,9 @@ export function logRenameEvent(level: RenameLogLevel, message: string, fields?:
     if (!fs.existsSync(renameLogPath)) {
       fs.writeFileSync(renameLogPath, "", "utf8");
     }
-    fs.appendFileSync(
-      renameLogPath,
-      `${new Date().toISOString()} [${level}] ${message}${formatFields(fields)}\n`,
-      "utf8"
-    );
+    const line = `${new Date().toISOString()} [${level}] ${message}${formatFields(fields)}\n`;
+    fs.appendFileSync(renameLogPath, line, "utf8");
+    writeToDailyRenameLog(line);
   } catch {
     // ignore write errors
   }