Replace pickers with composable Store backends

[bruno-f-cruz]

Retires clabe.pickers in favour of a composable Store — a four-method interface over the databases that hold rigs, task logic, trainer state and per-animal reconfigurations.

Implements the Pickers to Stores plan. Clean break — no deprecation shims. A companion PR against Aind.Experiment.VrForaging follows.

Why

DefaultBehaviorPicker fused data access, user prompting, Session construction and recency caching into one object, and DataversePicker subclassed it purely to swap one record — trainer state — for a different backend. That inheritance is the defect; composition was what was wanted.

What lands

clabe.ui — ambient frontend. Module-level passthroughs for every Frontend method, finishing the pattern notify() already started. Output methods (notify, header, activity) no-op headless; prompts raise NoFrontendError rather than hanging on a rig. Adds use_frontend() as a context-manager form of set_current_frontend for tests.

clabe.stores

Piece	Role
Kind[T]	Binds a record name to its pydantic model. from_rig / from_task / from_session / from_trainer_state fix the canonical names; the bare constructor snake-cases the model name for custom records.
Store	resolve (interactive) · list (headless) · write · scoped
StoreBase	Scope narrowing plus the default resolve policy: none raises, one auto-selects, many prompt.
CompositeStore	Routes per kind name to a backend.
LocalFileStore	The config library, behind a swappable Layout.
DataverseStore	Trainer state only, off the picker inheritance. Lives at clabe.stores.dataverse and is not re-exported from clabe.stores, because msal is a Windows-only dependency of the aind-services extra — the same convention as data_transfer.aind_watchdog.
MemoryStore	In-memory fake, for tests and headless assembly.

from clabe.stores import CompositeStore, LocalFileStore
from clabe.stores.dataverse import DataverseStore

store = CompositeStore(
    default=LocalFileStore(root=VR_LIB),
    routes={"trainer_state": DataverseStore()},
)
store = store.scoped(subject=session.subject)

SessionBuilder (clabe/session.py) keeps the one genuinely interactive job with no database behind it. It holds no hidden state, so recovery flows narrow a store explicitly instead of poking picker._session.

ByAnimalModifier moves to clabe.modifiers and reads/writes through a Store, so it stops reaching into picker.subject_dir.

Call-site accounting

Today	Becomes
picker.pick_rig(Model)	store.resolve(VR_RIG)
picker.pick_task(Model)	store.resolve(VR_TASK)
picker.pick_trainer_state(Model)	store.resolve(SUGGESTION)
picker.push_new_suggestion(ts)	store.write(SUGGESTION, ts)
picker.dump_model(rig)	store.write(VR_RIG, rig)
picker.pick_session(Session)	SessionBuilder(launcher).build()
picker.subject_dir	store.scoped(subject=...)

Hard constraint honoured

DefaultLayout reproduces the existing tree on \allen\aind\scratch\AindBehavior.db\... byte-for-byte: Rig/<COMPUTERNAME>/*.json, Task/*.json, Subjects/<subject>/{task,trainer_state}.json. No migration. The library-wide vs subject-specific task lookup — a nested try/while in pick_task — is now an ordered scope chain: subject folder first, then the shared library.

Deviations from the plan, and why

• ConfiergeStore is not in this PR. ConfiergeService only exists on the unmerged feat-add-ficus-adapter branch. The adapter slots in with no base-class change once that lands.
• SessionBuilder.subject_source dropped. The plan marked it an extension point with no caller; there is no sensible Kind for a bare subject string. Add it when something needs it.
• Bare-model automagic adopted. store.resolve(ManipulatorPosition) wraps the model in Kind(...) internally. The naming trap (Kind(AindVrForagingRig) → "aind_vr_foraging_rig", not "rig") is documented on Kind.
• Recency cache is now list ordering, not a separate prompt. The picker asked "pick from cache / select from library" as two steps; resolve now floats recently-chosen options to the top of one list. The picker's use_cache flag is gone — ordering never changes what is selectable.
• Trainer-state checks moved onto Kind.from_trainer_state's validator (reject stageless, warn off-curriculum), so both backends get them from one place.
• Overwrite-confirmation prompt on write is gone, per the plan: clobber behaviour is the store's contract.

Open

• write returns None. Revisit if a caller needs the written id.
• LocalFileStore.resolve offers the pick list only; no file-browse escape hatch yet.