[Docs]: Dir: intro page refinement for improved clarity to new viewers

[jodeev]

Issue Description

Objective

Clarify the differentiation of Agent Directory. The focus should be on explaining the core assumptions around how directory works, the core components of directory, the interaction with OASF & Agent record objects.

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Deliverables
The current content should be expanded to cover these points:

1. Directory Value prop
   • Articulate the purpose and value of agent directory in the context of agentic systems.
   • A succinct core positioning statement (noun phrase, 8-10 words max).
2. Scope and Role of directory
   • Clearly define what directory is and what it is not.
3. Unique Value Proposition
   • Describe what makes directory uniquely valuable.
   • Focus on just 3 key strengths for clarity and impact.
4. Ideal Users and Use Cases
   • Identify the characteristics of users who would benefit most from directory.
   • Outline specific scenarios where directory is most valuable.
5. Our Point of View
   • Articulate the team's strong opinions or guiding principles behind directory, such as:
     • The importance of a highly distributed system
     • the importance of skills and use of DHT
     • Why directory is essential for enabling interoperability across agentic systems.
6. Where to go to get started

Prposed Solution

Update content as described

Affected Component

CSIT

Checklist

• I have read the contributing guidelines.
• I have verified this does not duplicate an existing issue.