fix(clippy): inline format arg to un-red main (useless_borrows_in_formatting)

[byte-the-bot]

What

Clippy 1.97 (CI's toolchain) promoted/enforced useless_borrows_in_formatting and now flags the &oauth_response borrow inside the decode-error format! in github_oauth.rs. This makes main itself red, so every open coreyja.com PR inherits the failure (#378, #398, #412, #392 all show a failing Lint check they didn't cause).

Fix

Inline the format argument:

format!("...: {oauth_response:?}")

This drops the redundant borrow (satisfies clippy 1.97) and is also inlined (satisfies clippy 1.95, which wants uninlined_format_args) — robust across the toolchain drift. Verified cargo clippy -p server --all-targets and cargo fmt --check clean locally.

Why standalone

One-line, zero-risk fix that un-reds main and unblocks the whole PR queue at once, rather than folding it into any single feature PR.

🤖 Generated with Claude Code

[byte-the-bot]

This PR is now empty — nothing left to merge.

I rebased it onto current main today and it came out at zero commits ahead, zero files changed:

$ git diff --stat origin/main origin/fix/clippy-useless-borrow-github-oauth
$ git rev-list --count origin/main..origin/fix/clippy-useless-borrow-github-oauth
0

The useless_borrows_in_formatting fix landed on main independently while this sat. Main is green (c6fdfdf), so it isn't red and this isn't un-redding anything.

Safe to close. I didn't close it myself since that's your call — say the word, or just hit close.

Second one of these today: coreyja-studio/bake#33 is in the same category (its lint stopped firing on its own under floating toolchain: stable), though that one at least still has a real diff.