Set shared source-data fields (e.g. SpikeGLX stream) once in multi-session Locate Data

[rly]

Motivation

In the multi-session conversion workflow, interfaces with a required non-path source-data field (most visibly the SpikeGLX stream_id) required entering that field separately for every located session on the Source Data page. Since the value is almost always identical across sessions, this is tedious and error prone.

Closes #1085.

Change

On the Locate Data (path expansion) page, each interface's required non-path source-data fields are now shown alongside base_directory / format_string_path, so they can be set once for all sessions.

• The values are written to the project.SourceData globals that the Source Data page already applies to every session form, so they auto-fill each session and remain overridable per session. The existing Edit Default Values editor stays as the fallback for the non-locate_data path.
• project.SourceData is the only store for these values. beforeSave drops them from the persisted structure.results entry as well as from the neuroconv/locate payload (which rejects unknown props), and render seeds the form from project.SourceData on every page load, so a default edited from either page round-trips.
• The field description notes the value applies to all sessions and can be overridden per session.

Affected interfaces

The change is generic (any required, non-path field). Currently that surfaces:

Interface	Field	Type
SpikeGLXRecordingInterface	stream_id	string
TdtRecordingInterface	gain	number
ExtractSegmentationInterface	sampling_frequency	number
BrukerTiffMultiPlaneConverter	plane_separation_type	enum (disjoint/contiguous)

All four are already shown per-session today, so this only changes where they can be set, not whether they are exposed.

Testing

• Launched the app locally (Electron + Flask) to exercise the multi-session SpikeGLX flow.
• Validated the render-seeding and beforeSave routing logic with a standalone simulation (field added only for required non-path props, path props not duplicated, optional props excluded, shared schema not mutated, seeding from globals, local value not clobbered, routing to project.SourceData, stripping from the locate payload, file-vs-folder derivation, clearing a value, empty-format-string skip).
• Exercised the real render() and beforeSave() through the cross-page round trip (set the field on Locate Data, change it via Edit Default Values, revisit Locate Data, save again) to confirm the edited default is displayed and is not reverted.
• npm run test:app passes (91 tests).

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR improves the multi-session “Locate Data” (path expansion) step by surfacing required non-path source-data fields (e.g., SpikeGLX stream_id) on the Locate Data page so users can set shared defaults once, while still allowing per-session overrides later on the Source Data page.

Changes:

• Adds logic to expose required non-path source-data schema properties on the Locate Data form for each interface.
• Routes those shared field values into project.SourceData defaults (and strips them from the neuroconv/locate payload).
• Seeds the Locate Data form from existing project.SourceData defaults so values round-trip.

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[pauladkisson]

I confirmed that this works on my end. Sorry for the delay.

[rly]

All good. Thank you for the review!