[Deferred] Standalone OG-Core modelling layer (future work)

[Adityakushwaha2006]

What this adds

Backend support to run OG-Core inside MUIOGO as an independent modelling layer, with its own case
management, parameter handling, execution pipeline, and result retrieval. No coupling to CLEWS in
this scope.
OG-Core runs entirely on its own (Standalone , Uncoupled , Non-iterative)

Frontend is handled separately; this defines the API contract it will consume.

Scope

• OG-Core case and run management (CRUD), isolated from CLEWS storage.
• Per-run parameter persistence, including tax-function specifications that cannot be represented as JSON.
• Baseline and reform runs, with correct enforcement of the dependency a reform has on its baseline.
• Local execution covering steady state and (optionally) the full transition path, with run status tracking.
• Result retrieval: raw variables, OG-Core's standard analysis tables (macro aggregates, inequality,
  wealth distribution, revenue decomposition, time series), and a downloadable CSV export.
• Parameter schema endpoint so the frontend can build forms without hard-coding parameter metadata.
• Case backup and restore.

Constraints

• Non-destructive: no changes to existing OSeMOSYS/CLEWS routes, classes, or stored data.
• OG-Core must use its own namespace - endpoints, session key, storage folder, JSON key prefix - so it
  cannot collide with CLEWS cases.
• OG-Core runs as a locally installed Python package.
• Follow existing MUIOGO conventions for path security, response shape, and error handling.
• Pin an OG-Core version, update the Python requirement accordingly.

Acceptance criteria

• OG-Core cases and runs are fully independent of CLEWS.
• Baseline and reform runs can be configured, executed, and their results retrieved.
• OG-Core's own validation messages are surfaced cleanly to the caller on bad input.
• The existing CLEWS test suite passes without modification.
• Results through MUIOGO match results from running OG-Core directly with the same inputs.

Out of scope

• OG-Core/CLEWS coupling (planned separately).
• Frontend UI.
• Any changes to OSeMOSYS/CLEWS logic.

References

• Child Issue : Version Specifics for OG-CORE compatibility | [Question/Blocker] Version Support for OG-CORE | Bump minimum supported Python from 3.10 to 3.11 (required by OG-Core ≥0.15) #469

[SeaCelo]

Deferring this. The implementation in #471 ran OG-Core in-process inside MUIOGO's own environment; we've since settled on the opposite — OG country models run in their own environments, and MUIOGO neither installs nor imports OG-Core (#472). A standalone runner inside MUIOGO is also further out than where we are now.

Keeping this open as the home for the idea so it gets picked back up when the architecture supports it. See the close comment on #471 for what carries forward (the override-dict parameter model, the equivalence-check principle, the operation contract).