release: OfficeDex 0.6.7

[luyang950]

Summary

• round the sidebar OfficeDex brand icon corners
• prepare OfficeDex 0.6.7 release metadata
• bundle the pinned OfficeCLI 0.2.121 runtime

Verification

• TypeScript lint: passed
• Node release-script tests: 38/38 passed
• Renderer Vitest tests: 483/483 passed across 40 files
• Go tests: normal and officedex_demo builds passed across 15 tested packages each
• release metadata verifier: passed for package 0.6.7, Wails productVersion 0.6.7, and tag v0.6.7