ci: pin go 1.25.7 and use module-level go vet

- go.mod: go 1.26.5 -> 1.25.7 to match the golang:1.25 CI image (node-lookup convention)
- .pre-commit-config: dnephin go-vet runs at repo root (no .go files here since both
  tools live under cmd/); replace with a local 'go vet ./...' hook (CI pre-commit
  image has go)

.pre-commit-config.yaml

@@ -13,5 +13,16 @@ repos:
     rev: v0.5.1
     hooks:
       - id: go-fmt
-      - id: go-vet
       - id: go-unit-tests
+
+  # go-vet at the module level (dnephin's go-vet runs at repo root, which has no
+  # .go files here since both tools live under cmd/). The CI pre-commit image
+  # (almalinux9-gobuilder) has go installed.
+  - repo: local
+    hooks:
+      - id: go-vet-mod
+        name: go vet (module)
+        entry: go vet ./...
+        language: system
+        types: [go]
+        pass_filenames: false

go.mod

@@ -1,6 +1,6 @@
 module git.unkin.net/unkin/agent-tools
 
-go 1.26.5
+go 1.25.7
 
 require github.com/spf13/cobra v1.10.2