Fix PVOutput 10-minute gaps by using clock-aligned upload intervals

[rianbk]

Summary

• Fixes intermittent 10-minute gaps appearing on PVOutput intraday data approximately every hour
• Changes from elapsed-time tracking to interval-number tracking for upload timing

Problem

The previous code used time.time() - last_publish >= interval which caused uploads every ~5:30 instead of 5:00 due to processing time being added after each upload. This resulted in 11 uploads/hour instead of 12, causing one 5-minute slot to be skipped each hour.

Log evidence:

00:02:36 → 00:08:06 (5:30)
00:08:06 → 00:13:36 (5:30)
00:13:36 → 00:19:06 (5:30)

Solution

Use interval-number tracking aligned to clock boundaries:

current_interval = int(time.time() // (self.status_interval * 60))
if current_interval > self.last_uploaded_interval:

This ensures uploads align to clock boundaries (e.g., :00, :05, :10) with no drift.

Test plan

• Verified uploads now happen at exact 5-minute intervals (19:40:16 → 19:45:16 → 19:50:16)
• Confirmed countdown timer decreases correctly
• Monitor PVOutput intraday page for 24+ hours to confirm no gaps