fix(security): refresh uv installer checksum

Refresh the verified-installer pin for uv after the upstream Astral install script changed during the Ubuntu 25.10 Docker canary.

The canonical checksum refresh diff was limited to the generated timestamp plus the uv entry. ACFS security verification and automated_flywheel_setup_checker --check-hashes both report all 41 installer hashes matched after the refresh.

Verification:

- ./scripts/lib/security.sh --verify --json

- bash scripts/lib/test_security.sh

- automated_flywheel_setup_checker validate --path checksums.yaml --check-hashes

Author: Dicklesworthstone

checksums.yaml

@@ -1,4 +1,4 @@
-# checksums.yaml - Auto-generated 2026-05-06T15:43:01-04:00
+# checksums.yaml - Auto-generated 2026-05-06T16:15:21-04:00
 # Run: ./scripts/lib/security.sh --update-checksums
 
 installers:
@@ -156,7 +156,7 @@ installers:
 
   uv:
     url: "https://astral.sh/uv/install.sh"
-    sha256: "587b789920099623966262432910018f9072f9c5150d552cff4063d2422d2fb4"
+    sha256: "3a020f8d69019caca567c9038999d130b0ea85866483caf2042c386cb685aef4"
 
   xf:
     url: "https://raw.githubusercontent.com/Dicklesworthstone/xf/main/install.sh"