use rust caching in ci jobs

[dhth]

Standardize Rust setup with mise and cache Cargo artifacts across CI
jobs that compile the project. Disable dev-profile debug info to reduce
build time and cache size.

Build back-compat revisions in the default target directory so they
benefit from the cache.

Here’s data from two runs on the PR associated with this commit: the first had
no Rust cache available, while the subsequent run restored a full cache hit.

Job	First run	Cached run	Reduction	Cargo work
Build — Ubuntu	66s	21s	68%	44.66s → 3.20s
Build — macOS	132s	34s	74%	~84s → 8.62s
Lint	57s	28s	51%	36.85s → 3.25s
Back compatibility	67s	22s	67%	41.31s → 3.06s
Tests — Ubuntu	75s	26s	65%	50.33s → 4.96s
Tests — macOS	147s	52s	65%	~94.7s → 11.41s
Overall workflow	2m41s	1m03s	61%	—