docs: add business context, anonymize client name, unify language

[Repetto-A]

What

• Add "🌾 Context" section explaining the real-world use case (agricultural machinery dealer, Santa Fe, Argentina — why Telegram for field use)
• Anonymize client name: "Agromaq Quotation System" → "Agricultural Machinery Quotation System" + remove alt="Agromaq" from code snippet
• Rewrite the one-line description to English for a consistent audience signal

Why

• Recruiter/client reading this had no context for WHY the project exists or why Telegram specifically — now they do
• Client name anonymized until explicit consent is documented
• Description was in Spanish while README body was in English — mixed signal
• Screenshots are already committed and render correctly (verified)