Centralize slash_command routing for perf-improver, pr-fix, and test-improver

[Copilot]

gh aw compile --strict flagged these three workflows as outliers: they declared slash_command without centralized routing, causing duplicate per-workflow issue_comment triggers. This aligns them with the repository’s existing centralized slash-command pattern.

• What changed

  • Added on.slash_command.strategy: centralized in:
    • workflows/perf-improver.md (/perf-assist)
    • workflows/pr-fix.md (/pr-fix)
    • workflows/test-improver.md (/test-assist)

• Resulting behavior

  • Slash commands for these workflows are routed through centralized command handling (agentic_commands.yml) instead of generating duplicate local trigger wiring.

• Config pattern applied

  on:
    slash_command:
      name: pr-fix
      strategy: centralized