refactor: inherit Clippy lint config and Rust edition from workspace (#3782)

* refactor: inherit Clippy lint config and Rust edition from workspace

This also ensures developers running `clippy lint` locally get the same
lints as during CI, especially when the Rust toolchain version is fixed
through a `rust-toolchain.toml` file.

* chore(clippy.toml): bump MSRV to 1.87

apps/labrinth/Cargo.toml

@@ -2,7 +2,7 @@
 name = "labrinth"
 version = "2.7.0"
 authors = ["geometrically <jai@modrinth.com>"]
-edition = "2024"
+edition.workspace = true
 license = "AGPL-3.0"
 
 # This seems redundant, but it's necessary for Docker to work
@@ -131,3 +131,6 @@ actix-http.workspace = true
 dotenv-build.workspace = true
 chrono.workspace = true
 iana-time-zone.workspace = true
+
+[lints]
+workspace = true