Lint: Require `name` key in each `toc.yaml` entry

[martyanovandrey]

Description:
Each entry in toc.yaml must include a name key.

Current behavior:
Entries without a name key are accepted without errors.

Expected behavior:
Linting or validation should fail if an entry is missing the name key.

Steps to reproduce:

1. Add an entry to toc.yaml without a name key
2. Run linting or validation

Acceptance criteria:

• Linting fails if any toc.yaml entry does not have the name key
• Error message clearly indicates the missing name key and entry location