Docs(architecture): Clarify ADR content & fix grammar in architectural docs

[MarsonKotovi4]

PR Description:

• README.md: Refined the explanation of the difference between an ADR and a spec, adding clarity and minor grammar fixes.
• adr-002-docs-structure.md: Changed “non-related” to “unrelated,” updated references to “subfolders,” and improved overall wording to better explain the documentation structure.
• adr-003-dynamic-capability-store.md: Corrected grammar around object capability keys to ensure consistency and clarity regarding how the capability store is intended to work.

These updates aim to make the architectural documentation more cohesive and easier to follow, ensuring clear distinctions among ADRs, specs, and the overall docs structure.