chore(checksums): refresh cass installer SHA256 after upstream release

scripts/lib/security.sh --update-checksums regenerated checksums.yaml against
the live installer URLs. Only the `cass` (coding_agent_session_search) entry
moved:

  ba4c7635b0ba3d7c1a05f7e302729cb7567db01970bf7edf2b1eabedf5ca3a77
  → b4681bea9ce648aa4dcabada483e85a3925837156b8af9c204f912b7ac4407b4

cass cut a new release that landed at
https://raw.githubusercontent.com/Dicklesworthstone/coding_agent_session_search/main/install.sh,
which is the canonical install URL pinned in this file. Pulling the new SHA
in keeps the curl|bash supply chain verifiable for users running
./scripts/install-third-party.sh cass (or the equivalent install path that
verifies against checksums.yaml before sourcing the installer).

No other installer entries moved; the auto-generated timestamp updated to
2026-05-14T21:39:01-04:00.

Author: Dicklesworthstone

checksums.yaml

@@ -1,4 +1,4 @@
-# checksums.yaml - Auto-generated 2026-05-14T20:04:54-04:00
+# checksums.yaml - Auto-generated 2026-05-14T21:39:01-04:00
 # Run: ./scripts/lib/security.sh --update-checksums
 
 installers:
@@ -40,7 +40,7 @@ installers:
 
   cass:
     url: "https://raw.githubusercontent.com/Dicklesworthstone/coding_agent_session_search/main/install.sh"
-    sha256: "ba4c7635b0ba3d7c1a05f7e302729cb7567db01970bf7edf2b1eabedf5ca3a77"
+    sha256: "b4681bea9ce648aa4dcabada483e85a3925837156b8af9c204f912b7ac4407b4"
 
   claude:
     url: "https://claude.ai/install.sh"