Fix fuzz test length check for mention wrapping overhead

[Copilot]

The FuzzMentionsFiltering test was failing because its length check didn't account for mention neutralization overhead. When @user is sanitized, it becomes `@user`, adding 2 characters per mention.

Changes

• Updated length check formula from len(text) + len(text)/2 (1.5x) to len(text) * 7/2 (3.5x)
• Formula now accounts for: base length (1x) + general expansion (0.5x) + worst-case backtick wrapping (2x)
• Aligns with existing FuzzSanitizeIncomingText approach for consistency

Before:

if len(result.Sanitized) > len(text)+len(text)/2 {
    t.Errorf("Sanitized result is unexpectedly longer than input")
}

After:

expectedMaxLen := len(text) * 7 / 2
if len(result.Sanitized) > expectedMaxLen {
    t.Errorf("Sanitized result is unexpectedly longer than expected (input: %d, result: %d, expected max: %d)",
        len(text), len(result.Sanitized), expectedMaxLen)
}

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• https://api.github.com/user
  • Triggering command: /usr/bin/gh gh api user --jq .login 5054-28936/test-3690393186 GO111MODULE 5054-28936/test-3690393186/.gitattributes GOINSECURE GOMOD GOMODCACHE go ortc�� it/ref/tags/v5 stmain.go ache/go/1.25.0/x64/pkg/tool/linux_amd64/vet GOINSECURE GOMOD GOMODCACHE ache/go/1.25.0/x64/pkg/tool/linu--log (http block)
  • Triggering command: /usr/bin/gh gh api user --jq .login -json GO111MODULE ps GOINSECURE GOMOD GOMODCACHE ps fere�� ference.git GO111MODULE /opt/hostedtoolcache/go/1.25.0/x64/bin/go GOINSECURE GOMOD GOMODCACHE go (http block)
  • Triggering command: /usr/bin/gh gh api user --jq .login it/ref/tags/v5 GO111MODULE .cfg GOINSECURE GOMOD GOMODCACHE SKxUVknvXufI3/2ZUc9vejZHNutLcI0TfW/k1CYBPiUyEBsv--jq env ry=1 GO111MODULE 4218661/b370/_pkg_.a GOINSECURE 8ee817ca88b8f643-rf GOMODCACHE go (http block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

Investigate fuzzed test failure. https://github.com/githubnext/gh-aw/actions/runs/20278163482/job/58232895092

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