list_instruments() still logs loader-probe warnings on every call

[jepegit]

Problem

cellpy.readers.data_structures.instrument_configurations() is the right way to
discover loaders (it's what print_instruments uses), but for an app it has two
rough edges:

1. It logs a WARNING per non-loader module on every call — config_declarations,
   contract, hooks, declarations, registry, testing, and custom
   ("Missing instrument definition file"). A GUI calling it at startup has to
   bracket it with a log-level bump to keep the console clean.
2. The result isn't display-ready — ids like maccor_txt / pec_csv need a
   human label, and the raw file suffix/extension isn't returned alongside the
   models, so apps keep their own label + extension map.

Suggestion

A quiet, app-facing helper, e.g.:

cellpy.list_instruments()
# -> [{"id": "maccor_txt", "label": "Maccor (text)",
#      "models": ["one","two","three", ...], "suffixes": [".txt"]}, ...]

that (a) does not emit warnings for skipped/non-loader modules, and (b) includes a
human label and the raw suffix(es). This would let apps build an instrument picker

• ingestion form directly from cellpy.

---

Found while building cellpy-simple-gui on cellpy 2.1.0.post1. Full write-up with all items: CELLPY_PAINPOINTS.md.

[jepegit]

Reopening for the warnings half of this issue. The app-facing
cellpy.list_instruments() added in 2.1.1 is great — it returns id / label /
models / suffixes, exactly what was needed, so the "no labels/suffixes" part is
fully solved. 🙏

What's still open: calling it (or instrument_configurations()) still logs a
WARNING per skipped non-loader module on every call, so an app that wants a
clean console has to bracket it with a log-level bump.

Repro on cellpy 2.1.1.post1:

import logging, cellpy
logging.basicConfig(level=logging.INFO)
inst = cellpy.list_instruments()   # emits ~10 warnings before returning 13 loaders

WARNING:root:Could not create loader for arbin_sql_config: module '...arbin_sql_config' has no attribute 'DataLoader'
WARNING:root:Could not create loader for config_declarations: module '...config_declarations' has no attribute 'DataLoader'
WARNING:root:Could not create loader for contract: module '...contract' has no attribute 'DataLoader'
WARNING:root:Could not create loader for custom: Missing instrument definition file (not given and not defined in config)
WARNING:root:Could not create loader for declarations: ...
WARNING:root:Could not create loader for harmonize: ...
WARNING:root:Could not create loader for hooks: ...
WARNING:root:Could not create loader for maccor_txt_native: ...
WARNING:root:Could not create loader for registr: ...
WARNING:root:Could not create loader for testing: ...

These are also logged on the root logger (WARNING:root:), not a cellpy.*
logger, which makes them harder to filter selectively.

Suggestions (either works):

• Skipping a known non-loader module (no DataLoader, or a custom loader with no
  definition file) is expected discovery, not a problem — log it at DEBUG, not
  WARNING; or
• have list_instruments() specifically swallow the probe failures for modules it
  is going to skip anyway, so the public helper is quiet by contract.

Workaround in the app today (core/cellpy_adapter.py): temporarily raise the root
logger to ERROR around the call.

(The remaining true nice-to-haves — lightweight metadata read, per-instrument
metadata schema, figure theming — are tracked in #791.)