chore: Cleanup Cargo profiles (#21214)

## Which issue does this PR close?

- N/A

## Rationale for this change

* Don't explicitly set default values when configuring profiles. For
example, `release-nonlto` explicitly set several build settings (e.g.,
`opt_level`, `overflow_checks`) to their default values, which could be
misleading.
* Fix typos, reorder profile configuration, and other general cleanup

No functional changes.

## What changes are included in this PR?

## Are these changes tested?

Yes.

## Are there any user-facing changes?

No.

Author: neilconway

Cargo.toml

@@ -224,62 +224,57 @@ unused_qualifications = "deny"
 # --------------------
 # Compilation Profiles
 # --------------------
-#  A Cargo profile is a preset for the compiler/linker knobs that trade off:
+# A Cargo profile is a preset for the compiler/linker knobs that trades off:
 # - Build time: how quickly code compiles and links
 # - Runtime performance: how fast the resulting binaries execute
 # - Binary size: how large the executables end up
 # - Debuggability: how much debug information is preserved for debugging and profiling
 #
+# To use a profile: `cargo [ build | run | ... ] --profile <profile-name>`
+#
 # Profiles available:
-# - dev: default debug build; fastest to compile, slowest to run, full debug info
-#     for everyday development.
-#     Run: cargo run
-# - release: optimized build; slowest to compile, fastest to run, smallest
-#     binaries for public releases.
-#     Run: cargo run --release
-# - release-nonlto: skips LTO, so it builds quicker while staying close to
-#     release performance. It is useful when developing performance optimizations.
-#     Run: cargo run --profile release-nonlto
+# - dev: default debug build; fastest to compile, slowest to run, full debug info.
+#     For everyday development; default for "cargo [ build | test | run ]".
+# - release: fully optimized build; slowest to compile, fastest to run, smallest
+#     binaries. For public releases; default for "cargo [ bench | install ]".
+# - release-nonlto: skips LTO, so it builds much faster while staying close to
+#     release performance. Useful when developing performance optimizations.
 # - profiling: inherits release optimizations but retains debug info to support
 #     profiling tools and flamegraphs.
-#     Run: cargo run --profile profiling
-# - ci: derived from `dev` but disables incremental builds and strips dependency
-#     symbols to keep CI artifacts small and reproducible.
-#     Run: cargo run --profile ci
-# - ci-optimized: derived from `release` but enables debug assertions, and uses
-#     lighter optimizations. Used for long-running CI tasks.
-#     Run: cargo run --profile ci-release
+# - ci: derived from `dev` but disables debug info and incremental builds to keep
+#     CI artifacts small and reproducible.
+# - ci-optimized: derived from `release` but enables debug assertions and uses
+#     less aggressive optimizations for faster builds.  Used for long-running CI
+#     tasks.
 #
 # If you want to optimize compilation, the `compile_profile` benchmark can be useful.
 # See `benchmarks/README.md` for more details.
 [profile.release]
 codegen-units = 1
 lto = true
-strip = true      # Eliminate debug information to minimize binary size
+strip = true      # Eliminate debug info to minimize binary size
 
 [profile.release-nonlto]
-codegen-units = 16
-debug-assertions = false
-incremental = false
 inherits = "release"
+codegen-units = 16
 lto = false
-opt-level = 3
-overflow-checks = false
-rpath = false
-strip = false            # Retain debug info for flamegraphs
+strip = false        # Retain debug info for flamegraphs
+
+[profile.profiling]
+inherits = "release"
+debug = true
+strip = false
 
 [profile.ci-optimized]
 inherits = "release"
 debug-assertions = true
 codegen-units = 16
 lto = "thin"
-strip = true
 
 [profile.ci]
-debug = false
 inherits = "dev"
+debug = false
 incremental = false
-debug-assertions = true
 
 # This rule applies to every package except workspace members (dependencies
 # such as `arrow` and `tokio`). It disables debug info and related features on
@@ -289,8 +284,3 @@ debug = false
 debug-assertions = false
 strip = "debuginfo"
 incremental = false
-
-[profile.profiling]
-inherits = "release"
-debug = true
-strip = false