Review IntentRecord/SolverRecord field types/ordering for storage footprint

[james2177]

Description

IntentRecord (lib.rs:60-80) and SolverRecord (lib.rs:96-107) mix Option fields, Strings, and various integer widths. A review of field ordering and whether any field could use a narrower type without losing necessary range would help minimize per-entry storage footprint.

Requirements and context

• Go field-by-field through both structs and note the realistic value range each needs to hold

Suggested execution

1. Fork the repo and create a branch

   git checkout -b perf/struct-field-footprint-review
   

2. Propose and, if net-positive, implement any type-narrowing changes
3. Add/adjust tests for any changed field types, especially around serialization

Example commit message
chore: review intentrecord/solverrecord field types/ordering for st

Guidelines

• Assignment required before starting -- comment on the issue to claim it
• PR description must include: Closes #<this issue's number>
• Complexity: High (200 points)