[WIP] Ensure collectionDBPath exists with os.Mkdirall

[Copilot]

• Understand the issue: collectionDBPath needs os.MkdirAll to ensure the directory exists (similar to fileAssets)
• Add os.MkdirAll(collectionDBPath, 0755) to the init() function in main.go
• Verify the change builds correctly
• Run code review
• Run CodeQL security scan (no issues found)

Original prompt

On main.go, in main.go, we need to be sure also collectionDBPath does exists with os.Mkdirall

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