[Enhancement] Populate `parent_simulation_id` from Case Canonical + Surface in Simulation Details

[tomvothecoder]

Summary

Backfill and maintain parent_simulation_id on Simulation records by referencing the canonical_simulation_id of the associated Case.

Expose parent_simulation_id on the Simulation Details page for non-canonical simulations, with a link to the parent (canonical) simulation.

Motivation

• The canonical simulation acts as the baseline for a Case.
• Non-canonical simulations conceptually derive from the canonical configuration.
• Explicitly storing parent_simulation_id improves:
  • Data clarity
  • Query simplicity
  • UI linking
  • Future diff/comparison workflows

Currently, this relationship is implicit via case.canonical_simulation_id. It should be materialized on the Simulation model.

Proposed Changes

1. Backend: Backfill Logic

For all existing simulations:

• If simulation.id == case.canonical_simulation_id
  → parent_simulation_id = NULL
• Else
  → parent_simulation_id = case.canonical_simulation_id

Implementation options:

• Data migration (preferred)
• One-time script executed in migration context

Edge cases:

• Cases with canonical_simulation_id IS NULL
  • Do not populate parent_simulation_id
• Orphaned simulations (should not exist; validate)

2. Backend: Ingestion Logic

On simulation creation:

• Fetch the associated Case
• If:
  • No canonical exists → this simulation becomes canonical → parent_simulation_id = NULL
  • Canonical exists → set parent_simulation_id = case.canonical_simulation_id

Ensure this logic runs atomically within the same transaction.

3. API Updates

Include parent_simulation_id in:

• Simulation detail response
• Simulation list responses (optional but recommended for consistency)

4. Frontend: Simulation Details Page

If simulation is non-canonical:

Display:

Parent Simulation: <execution_id> (linked)

Link target:
/simulations/{parent_simulation_id}

If canonical:

• Do not show parent field.

Placement:

• Configuration or Metadata section
• Do not elevate to badge or header

Acceptance Criteria

• All non-canonical simulations have parent_simulation_id populated.
• Canonical simulations have parent_simulation_id = NULL.
• Simulation Details page displays parent link only when applicable.
• No change to existing canonical logic or promotion rules.

Non-Goals

• No support for multi-level ancestry.
• No diff computation changes.
• No case modeling changes.
• No automatic canonical reassignment logic.

[tomvothecoder]

Need clarification on whether or not this is the correct design before proceeding.

[tomvothecoder]

parent_simulation_id is no longer needed since cases are the aggregate root of simulations (referred to as executions).

Simulations can back-reference a case through parent-child relationship.