Fix a slow first Run again after boot

The first Run again after a station booted could take three times longer than the following ones, because the run start reopened the station's local state file four times while the previous run's upload was still writing to disk.

• Fixed the run start to open the local state file once, so Run again takes about 220 ms from the click to the first prompt, first cycle included
• Reduced disk writes at every run start, which also spares the SD card on Raspberry Pi stations