Fix: Last step of convergence loop can report false failure

[aqk]

The convergence loop exits when either prev_repr == this_repr (success) or steps >= CONSTANT_GENERATIONS_ALLOWED (failure). The post-loop check if steps == CONSTANT_GENERATIONS_ALLOWED cannot distinguish those two cases when convergence actually happens on the very last allowed iteration, and will incorrectly raise "Constant generation didn't converge in allowed iteration limit" for a program that did in fact converge.

Changes Made
Made the limit configurable (src/compiler/comptypes.rs, src/compiler/compiler.rs): Added constant_generation_limit() / set_constant_generation_limit() to CompilerOpts, DefaultCompilerOpts, and the delegation trait. This allows tests to exercise the boundary condition with small limits.

Wrote a regression test (src/tests/compiler/modules.rs): test_convergence_loop_boundary_does_not_false_positive sets the limit to 1 and compiles a module that converges in one iteration, directly triggering the false-positive error.

Fixed the check (src/compiler/codegen.rs): Changed from if steps == generation_limit to if prev_repr != this_repr, which directly tests whether convergence actually happened regardless of step count.

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Note

Medium Risk
Touches the module constant-generation convergence loop and compiler option plumbing; while the behavioral change is small, it affects core codegen termination/error conditions for module compilation.

Overview
Fixes a boundary-condition in the module constant-generation convergence loop so compilation no longer errors when convergence happens on the last allowed iteration (post-loop check now verifies prev_repr != this_repr rather than relying on the step counter).

Makes the convergence iteration limit configurable via CompilerOpts (constant_generation_limit + setter), wires it through DefaultCompilerOpts, and adds a regression test that sets the limit to 1 to exercise the failing edge case.

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[aqk]

We will make a smaller, more focused PR