Update wasm and next-custom-transforms crates to Rust edition 2024 (#90350)
The `wasm` and `next-custom-transforms` crates were still on Rust edition 2018 while the rest of the crates in this repo use edition 2024. This caused a pre-commit hook conflict:
- `cargo fmt` passes the crate's own edition (2018) to `rustfmt`, which uses **case-insensitive** import sorting
- The lint-staged pre-commit hook runs `rustfmt --edition 2024 --`, which uses **ASCII order** import sorting (uppercase before lowercase)
These two sort orders disagree on items like `{custom_before_pass, TransformOptions}` vs `{TransformOptions, custom_before_pass}`, causing an infinite flip-flop: every commit would reorder imports, and the next `cargo fmt` would reorder them back.
## Changes
- Bump `crates/wasm` and `crates/next-custom-transforms` from edition 2018 to 2024
- Add `+ use<C>` precise capturing to `server_actions()` return type to satisfy edition 2024's stricter `impl Trait` lifetime capture rules
- Add `style_edition = "2024"` to `.rustfmt.toml` as a safety net so `cargo fmt` uses 2024-style formatting regardless of individual crate editions
- Reformat all affected files with `cargo fmt`
- Apply new clippy rules