Chameleon

Fixed

• The call-graph tools now accept a repo-relative file_path. get_callers,
  get_blast_radius, get_callees, get_duplication_candidates, and
  query_symbol_importers ran find_repo_root on the raw file_path, so a
  relative path (the natural form: the calls index keys, search_codebase, and
  describe_codebase all emit relative paths) resolved against the server's
  working directory instead of the repo and the tool failed open with a bare
  {found: false} and no reason, a silently-wrong "no callers" on valid input.
  Each tool now resolves a non-absolute file_path against its repo argument's
  root first, and tags the genuinely-unresolvable case reason: "path-unresolved"
  so it fails loud. This most helps a weaker driving model (e.g. Sonnet), which
  would otherwise relay the empty answer rather than self-correct.