refactor: replace magic numbers with named constants in range check

[Lil-Duckling-22]

Replace hardcoded magic numbers in AssertLeFindSmallArcs with well-documented named constants. These constants represent mathematical values derived from Cairo's PRIME for range checking optimization. Improves code readability and maintainability by making the mathematical meaning explicit.

[reviewable-StarkWare]

This change is 

[orizi]

Reviewable status: 0 of 1 files reviewed, 1 unresolved discussion

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crates/cairo-lang-casm/src/hints/mod.rs line 17 at r1 (raw file):

mod test;

/// Mathematical constants for Cairo range checking algorithm.

constants used only once - define in function.

[orizi]

Reviewable status: 0 of 1 files reviewed, 2 unresolved discussions (waiting on @Lil-Duckling-22)

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crates/cairo-lang-casm/src/hints/mod.rs line 716 at r2 (raw file):

                let prime_over_3_high = 3544607988759775765608368578435044694_u128;
                // ceil((PRIME / 2) / 2^128) where PRIME = 2^251 + 17*2^192 + 1
                let prime_over_2_high = 5316911983139663648412552867652567041_u128;

prime in this context is known to be that value.

Suggestion:

                // ceil((PRIME / 3) / 2^128)
                let prime_over_3_high = 3544607988759775765608368578435044694_u128;
                // ceil((PRIME / 2) / 2^128)
                let prime_over_2_high = 5316911983139663648412552867652567041_u128;