Add NWB inspection API with automatic reader detection

[ilkilic]

Summary

Add a public inspect_nwb() API for parsing and inspecting NWB files without requiring callers to know the file layout or protocol names in advance.

Changes

• Add inspect_nwb() to automatically:
  • detect the appropriate NWB reader
  • discover available protocols
  • parse all traces by default
  • return the selected reader name
  • return lightweight file-level metadata
• Add NWBInspectionError for unsupported, invalid, or unparseable NWB files.
• Refactor nwb_reader() to reuse the shared reader-selection logic while preserving its existing interface.
• Support BBP, VU, AIBS, TRT, and Scala NWB layouts.
• Add tests for protocol discovery, metadata extraction, protocol filtering, invalid files, missing protocols, and layout detection.

Example

from bluepyefe.reader import inspect_nwb

result = inspect_nwb("recording.nwb")

[AurelienJaquier]

looks good, thanks!