Fixed clock-change date ranges and blocks displayed at the wrong hour

[vagisha]

Summary

• The billing exports and the scheduled-time pages end their date range at midnight after the chosen
  end date. For an end date on a clock-change Sunday the range ended at 1 AM or 11 PM instead.
• The scheduler calendar receives block times without a time zone, so it displays them at the Pacific
  hours shown in their tooltips whatever the browser's time zone. With the old Date.toString() times,
  a browser outside Pacific time displayed each block at a different hour.
• Billed and quota hours are unchanged. They count elapsed hours, so a block across a clock change
  counts one hour less or more than its clock times. UsageBlockBase.getHours() now documents this, and
  a test records it.

Test plan

• TimeUtilsTest and JSONInstrumentUsageGetterTest pass, and fail against the old end-of-day
  calculation and the old Date.toString() event times
• UsageBlockBaseTest passes. 10 PM to 6 AM counts 8 hours with no clock change, 7 across spring
  forward and 9 across fall back
• On a rebuilt war, the Lumos calendar for project 510 in November 2025: the feed sends
  2025-10-31T10:00:00 and 2025-11-02T04:00:00, the block reads "10a - 4a", its tooltip matches, and in
  week view it ends at the 4am line on Sunday 11/2. A browser set to Eastern time shows the same hours,
  where the old format would have shown 1p - 7a

Co-Authored-By: Claude noreply@anthropic.com

[Copilot]

🟢 Approval recommended

The DST fixes are correct, focused, and covered by representative regression tests.

Pull request overview

Corrects DST-related date boundaries and scheduler calendar rendering while preserving elapsed-hour billing behavior.

Changes:

• Advances end dates by one calendar day instead of 24 hours.
• Emits timezone-free ISO calendar event timestamps.
• Documents and tests elapsed-hour calculations across DST transitions.

File summaries

File	Description
TimeUtils.java	Fixes end-of-day calculation across DST changes.
TimeUtilsTest.java	Tests ordinary and DST boundary dates.
JSONInstrumentUsageGetter.java	Formats calendar events as local ISO timestamps.
JSONInstrumentUsageGetterTest.java	Tests event formatting across server time zones.
UsageBlockBase.java	Documents elapsed-hour semantics.
UsageBlockBaseTest.java	Tests hour totals across DST transitions.

Review details

• Files reviewed: 6/6 changed files
• Comments generated: 0
• Review effort level: Balanced

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.