Capture change proposals for a skill in Database

[cteyton]

Using the diff and diff --submit command, users must be able to submit change proposals to skills, including:

• The SKILL.MD file
• Any asset file within the skill, including its content and permissions. See: https://agentskills.io/specification

We must handle the following changes:

Changes linked to SKILL.md file

• updateSkillName => Skipped. According to the Agent Skills specs, name must match the parent directory name. It means we should detect upper directory renaming or move. Which is too tricky.
• updateSkillDescription
• updateSkillPrompt
• updateSkillMetadata
• updateSkillLicense
• updateSkillAllowedTools

Changes linked to additional file in skills

• addSkillFile
• updateSkillFileContent
• updateSkillFilePermissions
• deleteSkillFile

updateSkillFilePath is skipped so far, we'll consider it's a addSkillFile and deleteSkillFile

Example of output

Note: for the moment, results are only available in the database, not in the web app.

[stevdrouet]

• If there is a new binary file in diff, the output is bugged

[cteyton]

• Same for submission

[quentinlebourles-packmind]

• Petit problème de display lorsque des lignes sont fusionnés sur la même ligne

[cteyton]

• If there is a new binary file in diff, the output is bugged

Fixed when new files are added:

And when existing non-textual files are diffed:

[MaloPromyze]

• File permission changes are raised after fresh install

Otherwise LGTM

[cteyton]

• File permission changes are raised after fresh install

Otherwise LGTM

Thanks Malo.

Actually, it seems we don't properly handle SkillFile permissions.
On Upload, they're always hardcoded to cf readSkillDirectory

files.push({
          path: fullPath,
          relativePath: normalizedPath,
          content,
          size: Buffer.byteLength(content, isBinary ? 'base64' : 'utf-8'),
          permissions: 'rw-r--r--', // Simple default
          isBase64: isBinary,
        });

On install, we use default OS permissions, we don't use permissions returned by backend.
I'll fix this also.