chore(go): bump toolchain 1.25.7 -> 1.25.9 for additional stdlib CVEs

Second govulncheck sweep surfaced crypto/x509 + archive/tar + os +
net/url fixes landed in 1.25.8 and 1.25.9. Jump straight to 1.25.9
to close every known-reachable stdlib vuln in one commit.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: aksOps

go.mod

@@ -1,6 +1,6 @@
 module github.com/RandomCodeSpace/docsiq
 
-go 1.25.7
+go 1.25.9
 
 require (
 	github.com/google/uuid v1.6.0