feat(core): OSCAL assessment-results emitter + finding->control linker

Assess our findings against catalog controls and emit a standard OSCAL 1.1
assessment-results document — the assessment half of the loop (their catalog,
our assessment).

- ControlLinker maps a Finding's CWE -> catalog control-ids (CRA seed mirrors
  breakpilot's _CWE_TO_REQ; extensible via ControlLinker::new)
- assess() builds an observation per linked finding + a per-control
  'not-satisfied' finding; reviewed-controls covers the full catalog set
- deterministic: stable uuid5 ids (adds uuid "v5" feature) + caller-supplied
  timestamp; pure (no DB/network)
- 3 lib tests

Not yet wired into a scan run — that lands with the control-driven router (PR-4).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Cargo.lock

@@ -5089,6 +5089,12 @@ dependencies = [
  "digest",
 ]
 
+[[package]]
+name = "sha1_smol"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bbfa15b3dddfee50a0fff136974b3e1bde555604ba463834a7eb7deb6417705d"
+
 [[package]]
 name = "sha2"
 version = "0.10.9"
@@ -6472,6 +6478,7 @@ dependencies = [
  "getrandom 0.4.1",
  "js-sys",
  "serde_core",
+ "sha1_smol",
  "wasm-bindgen",
 ]