v0.5.0

Added

• MCP tool annotations derived from each tool's governance risk_level, so
  clients can gate approval from tools/list alone. low tools advertise
  readOnlyHint: true; every other tool advertises readOnlyHint: false and
  destructiveHint: true. The medium tier includes deletes and hard
  power-offs, so a tool is never advertised as non-destructive on the strength
  of its tier. idempotentHint only repeats an explicit declaration. The exact
  level is published in _meta under io.github.AIops-tools/riskLevel. These
  are hints for the client; audit and undo are unchanged.