fix(report): correctly parse millisecond Unix timestamps in report expiration checks

[drazisil-codecov]

Summary

Coverage report processors (Jacoco, Cobertura, Clover) were incorrectly flagging valid reports as expired when timestamps were in milliseconds (13+ digits) instead of seconds (10 digits).

The Problem

The timestring.Date() library expects seconds-based Unix timestamps, but some tools emit millisecond timestamps (13 digits like 1768258631332). When passed directly to Date(), these are parsed incorrectly, causing valid reports to be flagged as expired.

Example from Sentry:

• Timestamp: 1768258631332 (milliseconds)
• Actual date: 2026-01-12 17:57:11 (only 2 days old - NOT expired!)
• Date() interprets it as: Year 58003 (overflow/incorrect)
• Result: ReportExpiredException even though the report is valid

Impact

This was causing ~1.5M false errors/month in Sentry:

• WORKER-Q95 (Clover): ~124K events
• WORKER-Q96 (Jacoco): ~1.06M events
• WORKER-Q97 (Cobertura): ~308K events

Solution

Added normalize_timestamp() helper that detects millisecond timestamps (13+ digits) and converts them to seconds before passing to timestring.Date().

Changes

1. base.py: Added normalize_timestamp() helper function
2. jacoco.py: Apply normalization before Date comparison
3. cobertura.py: Apply normalization before Date comparison
4. clover.py: Apply normalization before Date comparison

Testing

• Added comprehensive unit tests for normalize_timestamp() helper
• Added millisecond timestamp test cases to existing expiration tests
• Added explicit "not expired" tests with recent millisecond timestamps

Fixes WORKER-Q95, WORKER-Q96, WORKER-Q97

---

Note

Ensures coverage report expiration checks work with millisecond Unix timestamps by normalizing to seconds before timestring.Date() parsing.

• Adds normalize_timestamp() in languages/base.py to convert 13+ digit Unix timestamps to seconds
• Applies normalization in clover.py, cobertura.py, and jacoco.py; exception messages now include the original timestamp
• Clover retains DD-MM-YYYY to MM-DD-YYYY swap prior to normalization
• Adds unit tests: new tests for normalize_timestamp() and updated expiration tests for all three processors, including recent millisecond "not expired" cases

^{Written by Cursor Bugbot for commit e5eb9c4. This will update automatically on new commits. Configure here.}

[sentry]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.35%. Comparing base (5dd9a49) to head (e5eb9c4).
⚠️ Report is 1 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #652   +/-   ##
=======================================
  Coverage   93.35%   93.35%           
=======================================
  Files        1292     1292           
  Lines       47126    47138   +12     
  Branches     1567     1567           
=======================================
+ Hits        43994    44006   +12     
  Misses       2823     2823           
  Partials      309      309           

Flag	Coverage Δ
workerintegration	59.10% <14.81%> (-0.04%)	⬇️
workerunit	91.27% <100.00%> (+<0.01%)	⬆️

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[codecov-notifications]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ All tests successful. No failed tests found.

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[drazisil-codecov]

Addressed the review feedback:

Re: Missing truthy check (cursor[bot])
This was already fixed in the second commit - the code now checks if timestamp: before calling Date().

Re: Redundant comments
Removed the redundant inline comments. The docstring in normalize_timestamp() already explains the millisecond handling, so the inline comments were repetitive. Kept only the one in clover.py that explains the DD-MM-YYYY swap since that's a separate concern.