fix: terminate incompatible compiled plans

[hjcud]

Closes #78.

AWS Development cause

INT03 run 66956d2d-1e21-37e9-bd62-a510f248a239 received an immutable compiled plan whose executionSnapshot.initialCashAmount was 100000 instead of the contract-required fixed-scale 100000.00000000. BasicPlanRuntime.load correctly raised BasicPlanCompatibilityError(PLAN_CONTRACT_INVALID), but the production binding let it escape to the worker's generic exception handler, which returned the same SQS message five times as HANDLER_ERROR:BasicPlanCompatibilityError.

The Backend producer normalization fix is separately tracked in Idea2Strategy-backend#255. This PR deliberately does not relax the compiled-plan contract.

Fix

Translate any deterministic BasicPlanCompatibilityError at the immutable plan binding boundary into JobNotSatisfiable, preserving the exact PlanLoadFailure reason. The existing terminal publication path now emits one FAILED, retryable=false event and returns PERMANENT_FAILURE.

Regression

The test injects the exact observed scale-less 100000 plan field and proves:

• reason PLAN_CONTRACT_INVALID
• exactly one terminal result event
• retryable=false
• no retry outcome

Verification

• targeted regression passed
• all non-Docker tests passed (3 skipped)
• Ruff passed for the whole repository
• mypy passed for all 56 source files
• git diff --check passed