mac: centralize log path lookup

apps/macos/Sources/Clawdis/LogLocator.swift

@@ -0,0 +1,37 @@
+import Foundation
+
+enum LogLocator {
+    private static let logDir = URL(fileURLWithPath: "/tmp/clawdis")
+    private static let legacyLog = logDir.appendingPathComponent("clawdis.log")
+
+    /// Returns the newest rolling log (clawdis-YYYY-MM-DD.log) if it exists, falling back to the legacy single-file log.
+    static func bestLogFile() -> URL? {
+        let fm = FileManager.default
+        let rollingFiles = (try? fm.contentsOfDirectory(
+            at: logDir,
+            includingPropertiesForKeys: [.contentModificationDateKey],
+            options: [.skipsHiddenFiles])) ?? []
+
+        let newestRolling = rollingFiles
+            .filter { $0.lastPathComponent.hasPrefix("clawdis-") && $0.pathExtension == "log" }
+            .sorted { lhs, rhs in
+                let lDate = (try? lhs.resourceValues(forKeys: [.contentModificationDateKey]).contentModificationDate) ?? .distantPast
+                let rDate = (try? rhs.resourceValues(forKeys: [.contentModificationDateKey]).contentModificationDate) ?? .distantPast
+                return lDate > rDate
+            }
+            .first
+
+        if let rolling = newestRolling {
+            return rolling
+        }
+        if fm.fileExists(atPath: legacyLog.path) {
+            return legacyLog
+        }
+        return nil
+    }
+
+    /// Legacy path used by launchd stdout/err; exposed for plist generation.
+    static var legacyLogPath: String {
+        legacyLog.path
+    }
+}