Add tests for `summarizeFixes` ordering and truncation

[devblac]

Add tests for summarizeFixes ordering and truncation

Context

While tweaking text output, I realized summarizeFixes has no direct tests. I’m worried someone will reorder or truncate differently without noticing.
 

Problem

The ordering (removed, changed signatures, interface changes) and the max cap are untested, so regressions would slip through.
 

Expected behavior

summarizeFixes should keep the current ordering and respect the max limit regardless of input mix.
 

Scope / non-goals

• Only add tests (or minimal refactor for testability). No functional changes intended.
   

Acceptance criteria

• Tests verify the ordering: removed first, then changed signatures, then interface changes.
• Tests verify results are truncated to max without altering item text.
• No behavior change in production code except small refactors needed for testing.
   

Hints

• internal/report/text.go — summarizeFixes; add cases in text_test.go.