Add French localization for common phrases

[Zakmaf]

Description

This pull request completes the French localization (FR) for the BentoPDF self-hosted application by translating all remaining UI strings and tool catalog labels/subtitles from English to French.

Scope includes:

• Navigation and landing-page copy
• Feature and compliance sections
• FAQ/testimonials/support/footer strings
• Tool categories and individual tool names/subtitles (including stamps fields and metadata/security tools)

Motivation:

• Provide a fully consistent French UI for French-speaking deployments and avoid mixed-language screens.

Dependencies:

• None.

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

🧪 How Has This Been Tested?

Haven't tested the UI as i'm not really a developper, just contributing with the materials.

Checklist:

• Verified output manually
• Tested with relevant sample documents or data
• Wrote Vite Test Case (if applicable)

Expected Results:

French text should be displayed consistently accross the UI (no unstranslated English strings remain for the updated keys).

Actual Results:

Please someone could test this? Really new to github PR.

Checklist:

• I have signed the Contributor License Agreement (CLA) or my organization has signed the Corporate CLA
• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[github-actions]

All contributors have signed the CLA ✍️ ✅
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[Zakmaf]

I have read the CLA Document and I hereby sign the CLA