Constant KTSTR_KERNEL_HINT 

pub const KTSTR_KERNEL_HINT: &str = "set KTSTR_KERNEL to one of: \
    exact version (`6.14`), inclusive range (`6.14..7.0` or \
    `6.14..=7.0`), git source (`git+URL#tag=NAME`, \
    `git+URL#branch=NAME`, or `git+URL#sha=<40-hex>`), absolute or \
    `~`-prefixed path, or cache key. List cached keys with \
    `cargo ktstr kernel list`; build new ones with \
    `cargo ktstr kernel build`";

Shared skip / error hint for call sites that cannot proceed without a resolvable kernel. Phrased so the user sees the same wording regardless of which layer surfaced the failure — tests, CLI, monitor probes, and sidecar writers all point the operator at the same remediation. Referenced by the non-VM-boot skip paths in cache.rs, probe/btf.rs, monitor/mod.rs, test_support/eval/mod.rs, and test_support/mod.rs.

Format: caller prefixes the actionable first clause (e.g. “no vmlinux found”) and appends this constant as the remediation tail. Keeping the prefix per-caller lets each site name the specific artifact it needs while the KTSTR_KERNEL wording stays consistent.