Update Rust toolchain to 1.95

[adampetro]

Summary

• This change updates the development toolchain to Rust 1.95.0.
• All published crates declare Rust 1.88 as the minimum supported Rust version.
• CI checks all targets and features with Rust 1.88.0.
• The code fixes the compiler and Clippy warnings from Rust 1.95.
• The dependency update removes the obsolete unicode-segmentation version limit.
• The diagnostic snapshots include the Rust 1.95 output format.
• This change does not update trybuild.

Verification

• cargo +1.88.0 check --workspace --all-targets --all-features
• cargo fmt --all --check
• cargo clippy --all-targets --all-features -- -D warnings
• cargo test --all-features
• cargo build --release --all-features
• cargo build --release --examples --all-features
• cargo build --profile shopify-function --target wasm32-wasip1 --example shopify_function -p bluejay-typegen