Add `poc-memory graph organize TERM` diagnostic that finds nodes
matching a search term, computes pairwise cosine similarity, reports
connectivity gaps, and optionally creates anchor nodes.
Add organize.agent definition that uses Bash(poc-memory:*) tool access
to explore clusters autonomously — query selects highest-degree
unvisited nodes, agent drives its own iteration via poc-memory CLI.
Add {{organize}} placeholder in defs.rs for inline cluster resolution.
Add `tools` field to AgentDef/AgentHeader so agents can declare
allowed tool patterns (passed as --allowedTools to claude CLI).
