Feat/show collection diagnostics

[srimon12]

Summary

Add support for SHOW COLLECTION <name> to expose collection-level diagnostics from Qdrant.

This introduces a new statement that lets users inspect a single collection’s health and configuration directly from QQL, instead of only listing collection names via SHOW COLLECTIONS.

What changed

• Added a new AST node: ShowCollectionStmt
• Extended the parser to support:

  SHOW COLLECTION <name>

• Added executor support using QdrantClient.get_collection(...)
• Added CLI formatting for collection diagnostics output
• Documented the new command in:
  • README.md
  • docs/collections.md
  • docs/getting-started.md
  • docs/programmatic.md

Diagnostics exposed

SHOW COLLECTION <name> now returns:

• collection status
• point count
• indexed vector count
• segment count
• vector names and dimensions
• distance metric
• dense vs hybrid topology
• sparse vector modifiers when present
• quantization mode
• HNSW config
• payload schema / indexes
• shard / replica / write consistency settings

Follow-up hardening included

While validating the feature, I also tightened a few edge cases:

• avoid misreporting named dense-vector collections as hybrid
• handle missing payload_schema safely
• guard against missing vector configuration
• clean up repo Ruff findings touched during this work

Testing

Verified with:

uv run pytest -q
uvx ruff check .

Results:

• 431 passed
• All checks passed!