chore(clippy): apply pedantic auto-fixes (inline format args + method refs)

[runonthespot]

Summary

Mechanical `cargo clippy --fix` cleanup with three pedantic lints, opt-in just for this pass:

• `clippy::uninlined_format_args` — `format!("{}", x)` → `format!("{x}")`
• `clippy::redundant_closure_for_method_calls` — `.map(|x| x.to_string())` → `.map(ToString::to_string)`
• `clippy::needless_raw_string_hashes` — drop `#` when the raw string doesn't need them

27 files touched, all single-line substitutions. No logic changes, no behavior changes.

Why now

Reduces incidental fmt drift on future PRs (most files would otherwise gain one or two inlined-format-arg changes whenever someone touches them). One-time cleanup so the diff is concentrated rather than scattered.

What I did NOT do

• Did NOT add `#![warn(clippy::pedantic)]` to any crate. The default warn level remains the CI gate. If we wanted pedantic-strict permanently, that's a separate discussion (it has ~150 other warnings — some are good, many are noise).
• Did NOT touch any code with actual logic.

Verified

• `cargo check --workspace` clean
• `cargo fmt --all --check` clean
• `cargo clippy --workspace --all-features --all-targets -- -D warnings` clean (existing CI gate)
• ck-engine tests pass

🤖 Generated with Claude Code