fix: lint multiline MDX tags

[ayaanoncrypto]

Addresses issues #1806, #1795, and #1792.

What changed:

• Exclude the asset-only static directory from generated documentation indexes.
• • Update the MDX linter to inspect component attributes and image alt attributes when tags span multiple lines.
• • Regenerate docs/AGENTS.md after the index change.
    Why:
    The previous checks missed invalid metadata when a component tag or image attribute crossed a line boundary. The generated index also included a directory without documentation pages.

Testing:

• Node syntax checks passed.
• • Targeted multiline MDX fixture detected the missing Card title and missing image alt while accepting valid multiline tags.
• • git diff --check passed.
    The full existing repository lint baseline reports 1,447 errors and 74 warnings, so validation focused on the changed logic and a targeted regression fixture.

[cb-heimdall]

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