chore(frontend): remove stale v54.0-6d8b28047 directory

[imlinhan]

Active version is now v54.0-b249d142b. The old directory was left behind after rebase; rsync --delete only cleans inside the versioned dir.

Summary

Linked Issue

Change Type

• feat (new capability)
• fix (bug fix, no API change)
• refactor (internal cleanup, no behavior change)
• docs (documentation only)
• chore (build, CI, tooling, dependency updates)
• skill / strategy (YAML skill or .strategy.md / .template.md)

Affected Areas

• backend/src/agentv3/ (primary runtime: ClaudeRuntime, MCP server, verifier)
• backend/skills/ (YAML skills)
• backend/strategies/ (*.strategy.md, *.template.md, knowledge-*)
• perfetto/ui/src/plugins/com.smartperfetto.AIAssistant/ (frontend)
• scripts/ / backend/scripts/ (tooling, generators)
• .github/workflows/ (CI)
• Tests only

Done Conditions

• npm run verify:pr from repo root → green
• I included any extra targeted test command needed for this change in the test plan below
• New .ts / .yaml / .sh / .strategy.md files carry SPDX AGPL v3 header

Test Plan

Risk / Rollback

Notes for Reviewers