feat(repo-memory): add format-json option to pretty-print JSON files before commit

[Copilot]

AI agents frequently write JSON memory files as single-line blobs even when instructed otherwise, making them hard to review or manually correct in the repository. A new format-json: true option on repo-memory entries forces all .json files to be pretty-printed (2-space indent, trailing newline) before they are committed to the memory branch.

Changes

• RepoMemoryEntry struct — new FormatJSON bool field (format-json YAML key)
• extractRepoMemoryConfig — parses format-json in both object and array config paths
• buildPushRepoMemoryJob — emits FORMAT_JSON: 'true' env var on the push step only when enabled (omitted otherwise, no-op default)
• push_repo_memory.cjs — after files are copied but before git add, recursively formats .json files via JSON.stringify(parsed, null, 2); invalid JSON files are skipped with a warning rather than failing the push
• Schema — format-json boolean added to both the object and array-item repo-memory schema variants
• Docs — format-json documented in the advanced config example and option descriptions
• Tests — object config, array config, default-false, and push-step env-var emission

Example

tools:
  repo-memory:
    branch-name: memory/notes
    format-json: true   # pretty-prints all .json files before commit

Or per-entry in array notation:

tools:
  repo-memory:
    - id: notes
      branch-name: memory/notes
      format-json: true
    - id: logs
      branch-name: memory/logs