Refine hero subtitle copy to remove duplication

[PredictabilityAtScale]

Motivation

• Remove repeated messaging in the hero section by combining the strongest points from two subtitle paragraphs into a single, clearer lead paragraph.

Description

• Modified the hero block in website/index.html to replace two subtitle paragraphs with one consolidated lead that mentions prompts, model settings, tools, input validation, environment overrides, and tests, and highlights rendering provider-ready request bodies without sacrificing SDK/gateway/auth/retries/observability.
• Removed the separate section-intro section-intro-tight paragraph and merged its content into the p.lead copy to avoid duplication.
• The change is limited to the hero section of website/index.html and is copy-only (no behavioral or styling changes).

Testing

• Ran rg to search for the original duplicated phrases and confirmed the old duplicate paragraph is no longer present (success).
• Inspected the updated file with nl and sed to verify the hero text lines were updated as intended (success).
• Reviewed the hero section in website/index.html to confirm only the consolidated paragraph remains (success).

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Codex Task