chore(msrv): floor to 1.88, pin CI on the floor, allow uninlined_format_args

Declared rust-version and the ci.yml/qa.yml toolchain pins both sit at 1.88 (the
edition-2024 floor once zip 8 and let-chains are accounted for), so CI builds on
exactly the MSRV: an accidental bump to a newer toolchain fails CI by design and
moving the floor takes a deliberate pin edit. The uninlined_format_args allow
reconciles 1.88's clippy with the allow-by-default it became in 1.97+.

Cargo.toml

@@ -2,7 +2,7 @@
 name = "freemkv-keysources"
 version = "1.6.13"
 edition = "2024"
-rust-version = "1.97"
+rust-version = "1.88"
 license = "MIT"
 description = "Pluggable AACS key sources (keydb, online key service) for libfreemkv. Each source looks a disc up and hands libfreemkv its terminal Unit Keys via get_unit_keys; the library does all derivation."
 repository = "https://github.com/freemkv/freemkv-keysources"
@@ -41,3 +41,6 @@ codegen-units = 1
 # config-level [patch.crates-io] wins over this manifest one for the same crate).
 [patch.crates-io]
 libfreemkv = { git = "https://github.com/freemkv/libfreemkv", tag = "v1.6.12" }
+
+[lints.clippy]
+uninlined_format_args = "allow"