test(share): cover RowsWithNamespace boundaries

[loglapa]

Closes #3430

Summary

• cover inclusive minimum and maximum namespace boundaries
• cover overlapping rows, single-namespace rows, and namespaces outside all rows
• verify malformed row roots fail without returning partial matches
• fuzz row-range selection against a simple reference predicate

Validation

• go test ./share -count=1
• go test -race ./share -run TestRowsWithNamespace -count=1
• go test ./share -run '^$' -fuzz '^FuzzRowsWithNamespace$' -fuzztime=5s (218k+ executions)
• golangci-lint run ./share

[greptile-apps]

Greptile Summary

Adds focused unit and fuzz coverage for namespace-to-row matching, including inclusive boundaries, empty roots, malformed row roots, and generated ordered namespace ranges. The new deterministic tests and fuzz run completed successfully without revealing a behavioral failure.

Confidence Score: 5/5

No blocking failure remains.

The focused boundary, malformed-input, and fuzz coverage completed successfully, and no accepted blocking finding remains.

T-Rex Logs

What T-Rex did

• T-Rex completed the requested verification of the proof-of-work for the pull request.
• T-Rex noted that local artifact references were not uploaded as part of the verification.

_{Ran code and verified through T-Rex}

_{Reviews (3): Last reviewed commit: "test(share): fix import grouping" | Re-trigger Greptile}

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 37.71%. Comparing base (2469e7a) to head (f80f1dd).
⚠️ Report is 895 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5194      +/-   ##
==========================================
- Coverage   44.83%   37.71%   -7.12%     
==========================================
  Files         265      308      +43     
  Lines       14620    21409    +6789     
==========================================
+ Hits         6555     8075    +1520     
- Misses       7313    12310    +4997     
- Partials      752     1024     +272     

☔ View full report in Codecov by Harness.
📢 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.