fix: guard factory pool count overflow

[jamilahmadzai]

Closes #82

Bounty: GrantFox OSS campaign for issue #82

Summary

• return a typed FactoryError::PoolCountOverflow when the factory cannot allocate the next pool ID
• compute PoolCount with checked_add(1) before deploying or writing a pool record
• cover the u32::MAX boundary so overflow leaves the count unchanged and does not create a Pool(u32::MAX) record

Validation

• cargo fmt --all -- --check
• cargo test -p factory pool_count -- --nocapture
• cargo test -p factory create_pool -- --nocapture
• cargo test -p factory -- --nocapture
• cargo build
• cargo test --workspace -- --nocapture
• git diff --check

Notes

• factory/src/lib.rs now only uses saturating_add for bounded pagination and checked_add for the pool-count increment
• existing Soroban Events::publish deprecation warnings remain unchanged

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[prodbycorne]

fix Ci build

[jamilahmadzai]

Fixed the CI breakage after the upstream merge and updated the branch to current main at 9d36584. The merge had left a malformed workflow step, overlapping error code, stale factory integration-test API calls, and two adjacent function insertions without closing delimiters. Local validation now passes cargo fmt --all -- --check, release WASM builds, cargo clippy --workspace --all-targets -- -D warnings, and cargo test --workspace (130 tests).