Abort on panic in release builds

Use the abort panic strategy for release builds to reduce generated
code. A panic now terminates the process without unwinding the stack.

An isolated five-run comparison across three workloads reduced .text
size by 12.7% on the local x86-64 machine and 13.6% on Fedora AArch64.
The measured link-time differences were small relative to run-to-run
variation.

Validated release builds for all 20 targets and successful links for
all three workloads on both machines.

Cargo.toml

@@ -37,6 +37,7 @@ zstd = "0.13"
 [profile.release]
 debug = 1
 codegen-units = 16
+panic = "abort"
 
 [profile.dev]
 opt-level = 1