docs: README wording and formatting improvements

[dx4iot]

Changes Made

• Improved wording in project description
• Fixed minor grammar issues
• Improved clarity in Dagster and dbt descriptions
• Small formatting improvements in testing and containerization sections

Confirmation

• Only README.md was modified
• No code or configuration files were changed
• Changes are minor and preserve the original meaning

[Copilot]

Pull request overview

This PR refines README.md wording and Markdown formatting to improve clarity and readability of the project overview and key sections, without changing any code or configuration behavior.

Changes:

• Clarified and standardized wording in the framework overview and “Core Capabilities” bullets.
• Improved phrasing in the architecture description to read more naturally.
• Cleaned up formatting/indentation in the environment variables and testing sections for consistent Markdown rendering.

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[DevStrikerTech]

LGTM