feature: helm chart ingestor

[george-lhj]

Tasks

• URL normalize: parse owner/repo, optional ref, optional subdir
• Resolve ref: if not given, use default branch
• Locate chart root: if subdir provided, validate it contains Chart.yaml; else search for exactly one directory with Chart.yaml
• Parse files:
  Chart.yaml → chartName, version
  values.yaml → defaults (typed)
  values.schema.json (if present) → schema (or null on parse error)
• Scan templates/:
  Collect .Values.* references → discoveredKeys (dot-paths; allow ["key"] normalization)
  Detect required "msg" ; if references .Values.*, add requiredHints
  Docs (optional): read README.md (store limited text + path)

Output should be a chart bundle that is JSON shaped

Acceptance Criteria

• Given a valid GitHub chart URL, returns a populated ChartBundle matching the spec
• Works for both repo root and /tree// forms
• requiredHints captured for obvious required(...) usages
• Graceful handling when values.schema.json is missing or invalid