test: intentionally broken hornsound submission [NAT-135]

[tallnato]

Summary

• Adds a test hornsound entry (content/_hornsounds/Test-Broken-Hornsound/) with 4 intentional validation errors
• Missing audio field in frontmatter
• Wrong file extension (.aac instead of .mp3/.wav/.ogg)
• Missing title field in frontmatter
• Bad slug with uppercase characters (Test-Broken-Hornsound)

Expected CI Behavior

Both validate-pr.yml and validate-hornsounds.yml should fail.

Test plan

• Local validation confirms all 4 errors detected
• CI Validate PR workflow fails
• CI Validate Hornsounds Content workflow fails
• Results documented in PR comments

🤖 Generated with Claude Code

[tallnato]

CI Results (Expected Failures)

Both validation workflows failed as expected:

Check	Status
Validate PR	Failed
Validate Hornsounds Content	Failed
Semantic PR	Passed
Label	Passed
Single Component Check	Passed

Validation errors detected:

1. hornsounds/Test-Broken-Hornsound: folder name must be lowercase alphanumeric with hyphens
2. hornsounds/Test-Broken-Hornsound.md: missing required field "title"
3. hornsounds/Test-Broken-Hornsound/broken-horn.aac: invalid file type ".aac" (allowed: .mp3, .wav, .ogg)
4. hornsounds/Test-Broken-Hornsound.md: missing required field "audio"

Conclusion: Validation pipeline correctly catches all 4 intentional errors.

[tallnato]

Review: Approved ✔

PR meets all acceptance criteria from NAT-135:

• 4/4 intentional validation errors detected by CI:
  1. folder name must be lowercase alphanumeric with hyphens — bad slug (uppercase Test-Broken-Hornsound)
  2. missing required field "title" — no title in frontmatter
  3. invalid file type ".aac" — wrong extension (not .mp3/.wav/.ogg)
  4. missing required field "audio" — no audio field in frontmatter
• Both validate-pr.yml and validate-hornsounds.yml failed as expected
• PR is scoped to hornsound collection changes only (2 files)
• No security concerns — test data only, no secrets or credentials

The validation pipeline is working correctly. This PR should not be merged (it's intentionally broken test data for CI validation).

Reviewed by: Revinaldo (PR Engineer)