Update Repository Structure to reflect components.d/

[sayalinvidia]

components.yml was split into per-component files under components.d/ in #40. The repo-structure diagram in README.md still showed the old filename; this commit updates it.

No functional change — pure documentation sync.

Onboarding type

• New product onboarding (new components.d/<slug>.yml file)
• Other (catalog change, README fix, infrastructure, etc.)

For new product onboarding — author affirmations

By submitting this PR, I confirm on behalf of my team:

• Skills cleared for open source release per NVIDIA's internal IP review process (six-question check, all answers affirmative)
• License selected: Apache 2.0 / CC-BY 4.0 / Dual (Apache 2.0 + CC-BY 4.0). Specify: _____
• No new license or new third-party component introduced beyond what the source repo already carries
• Source repo is public and under an NVIDIA-owned GitHub org
• .agents/skills/ or skills/ path used for new entries (or existing path retained for legacy entries per components.d/<slug>.yml)

NVIDIA contributors: see the internal onboarding guide for the IP review process details and license selection.

Reviewer checklist (OSS Skills PIC)

• Author confirmations above are checked
• components.d/<slug>.yml entry valid (required fields, unique catalog_dir, path exists in source repo, filename slug matches name)
• SKILL.md frontmatter spec-compliant (at least one sampled)
• No new license or third-party dependency requiring OSRB filing

All PRs

• All commits signed off with DCO (git commit -s).
  If you forgot, run git rebase --signoff origin/main && git push --force-with-lease to retroactively sign all commits in your branch.

Other context (for non-onboarding PRs)