fix(cache): persist vary when updating sqlite cache entries

[trivikr]

This relates to...

Fixes: #5108

Rationale

SqliteCacheStore#set() reuses an existing row for the same URL/method, but the UPDATE statement did not include vary. That meant an entry could transition from non-varying to varying in memory while the SQLite row still held NULL, allowing later lookups to match unrelated request headers.

Changes

• update SqliteCacheStore's overwrite query to persist vary
• pass serialized value.vary through the update path in set()

Features

N/A

Bug Fixes

Fixed SqliteCacheStore failing to update vary when overwriting an existing cache entry

Breaking Changes and Deprecations

N/A

Status

• I have read and agreed to the Developer's Certificate of Origin
• Tested
• Benchmarked (optional)
• Documented
• Review ready
• In review
• Merge ready

Assisted-by: openai:gpt-5.4

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.14%. Comparing base (94c9dea) to head (c177a2d).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5109   +/-   ##
=======================================
  Coverage   93.14%   93.14%           
=======================================
  Files         110      110           
  Lines       35894    35896    +2     
=======================================
+ Hits        33432    33434    +2     
  Misses       2462     2462           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[mcollina]

lgtm