docs: align web layer text with infrastructure/commons framing

[TommiLindfors]

Aligns the workflow-web repository's public-facing text with Clarvia's infrastructure/commons framing:

• README: Reframes opening from emotional family appeal to 'thin web layer / reference consumer' description
• Meta description: Leads with infrastructure, keeps family benefit
• data.ts: Removes 'grant-ready' from source-visible comment; softens 'controlled public launch' to 'initial public availability'
• package.json: Adds missing description field

No changes to rendered website content (hero, heritage folder, service sections etc.) -- the website is the public service and must remain family-facing for the Oeuvre Nationale application.

Aligns with Clarvia's NLnet Commons Fund application framing while remaining consistent with the Oeuvre Nationale application.