v0.14.0

Board config file I/O + agent identity

New features

• identity field on AgentInstructions interface
• [key: string]: unknown index signatures on AgentInstructions and BoardConfig for extension field round-tripping
• New boardFile.ts module with:
  • parseBoardConfig(content) — parse YAML frontmatter board config
  • serializeBoardConfig(config, body) — serialize to markdown string
  • readBoardConfig(filePath) — read from disk
  • writeBoardConfig(filePath, config, body) — write to disk

Matches the existing taskFile.ts API pattern. Extension fields (x-otto, x-cursor) round-trip through all operations.