fix: close button and CSV import parsing for Clockify/Harvest

Close button did nothing when "close to tray" was disabled - the
onCloseRequested handler lacked an explicit destroy call for the
non-tray path.

Clockify CSV import threw RangeError because locale-dependent date
formats (MM/DD/YYYY, DD.MM.YYYY, 12h time) were passed straight
to the Date constructor. Added flexible date/time parsers that
handle all Clockify export variants without relying on Date parsing.

Added dedicated Clockify mapper that prefers Duration (decimal)
column and a new Harvest CSV importer (date + decimal hours, no
start/end times).

Bump version to 1.0.1.

src-tauri/tauri.conf.json

@@ -1,7 +1,7 @@
 {
   "$schema": "https://schema.tauri.app/config/2",
   "productName": "ZeroClock",
-  "version": "1.0.0",
+  "version": "1.0.1",
   "identifier": "com.localtimetracker.app",
   "build": {
     "beforeDevCommand": "npm run dev",