v2.4.6 — index status reads the store every command reads

Fixed

• cortex index status says an indexed repo is indexed. It asked the
  indexer by project name with no store pinned, which only looked in the
  legacy shared cache — and cortex index clears that cache once it has
  written the repo's own .cortex/db. So in any repo indexed the current way
  it answered "project not found or not indexed", while code find and
  index list saw the index in the same directory. It now reads the store
  every other command reads (.cortex/db, else the legacy .cortex/graph.db
  or shared cache), through the same check the MCP index_status tool now
  makes, so the two cannot disagree.

Changed

• index status / index_status report counts and identity. Both print
  Indexed: <name> at <root> (<n> nodes, <m> edges, last: <ts>), so the
  CLI's answer is a line rather than the indexer's JSON, and the MCP tool's
  gains the counts. When the store carries another checkout's identity —
  copied in, or left behind by a checkout that has moved — a Warning: line
  now says so; previously both reported it as this checkout's index.
  index_status also resolves the legacy stores and answers for the
  enclosing checkout when given a subdirectory.
• cortex index status exit codes. Not indexed (or an empty store) exits
  3 with cortex index . as the next step; outside a git repository it is a
  usage error (exit 2) rather than a query about a project with no name.