chore(lint): adopt the canonical .golangci.yml from infra/ci-templates

Canonical lives at infra ci-templates/golangci.yml, distributed by the
infra#309 pattern: byte-identical copies, checksum drift gate in infra. Do
not edit this file here -- edit the canonical and run `task ci:sync`.

Verified locally before pushing, not pushed-and-hoped: golangci-lint v2.11.4
against a Go 1.26.1 toolchain (matching CI) reports 0 issues here.

Also applies gofumpt, which this config enables and the golangci-lint v2
default set does not check at all. That gap is why the drift was invisible:
earlier passes ran gofmt, which is weaker. Mechanical, deterministic,
build+vet verified.

.golangci.yml

@@ -0,0 +1,52 @@
+# Canonical golangci-lint configuration for the estate's Go repos (infra#309
+# pattern: one canonical file here, a byte-identical copy in each adopter,
+# and the drift gate in THIS repo comparing sha256).
+#
+# Why this exists: 26 Go repos, 3 had a lint config, and all three were
+# different. The 23 without one ran golangci-lint's v2 default set, which
+# does NOT include a formatter -- so gofmt/gofumpt drift went uncaught until
+# it was found by hand (dma-cli#12: two files drifted, nothing flagged them).
+#
+# The two configs this replaces (cobalt-dingo, coo-agent) were near-identical
+# copies of each other AND both invalid under v2: they carried v1-style
+# `linters-settings` and `issues.exclude-rules` keys, which `golangci-lint
+# config verify` rejects outright. Their revive settings and test exclusions
+# were therefore not in effect. Consolidating fixes that too.
+#
+# Per-repo variation does NOT belong here -- this file must stay byte-identical
+# across adopters so the gate is a checksum, not a diff a human has to judge.
+# A repo with a genuine exception (agentsquad excludes its seeded-bug fixture
+# tree, which exists precisely to contain broken code) keeps its own config and
+# is not listed as an adopter.
+
+version: "2"
+
+linters:
+  default: none
+  enable:
+    - errcheck # unchecked errors
+    - govet # suspicious constructs
+    - staticcheck # broad static analysis
+    - unused # unused code
+    - misspell # spelling
+    - revive # idiomatic Go
+    - exhaustive # exhaustive switch on enums
+
+  settings:
+    revive:
+      rules:
+        - name: var-naming
+          severity: warning
+
+  exclusions:
+    rules:
+      # Test files: table-driven cases legitimately carry unused struct fields
+      # and long functions.
+      - path: _test\.go
+        linters:
+          - revive
+          - unused
+
+formatters:
+  enable:
+    - gofumpt

internal/gitea/client_guard_test.go

@@ -27,8 +27,8 @@ func TestEmptyPathSegmentRejectedBeforeNetwork(t *testing.T) {
 	c := gitea.NewClient(srv.URL, "tok")
 
 	paths := []string{
-		"/api/v1/repos/mathias//issues",        // empty repo
-		"/api/v1/repos//gitea-mcp/contents/",    // empty owner
+		"/api/v1/repos/mathias//issues",            // empty repo
+		"/api/v1/repos//gitea-mcp/contents/",       // empty owner
 		"/api/v1/repos/mathias//issues?state=open", // empty repo before query
 	}
 	for _, p := range paths {

internal/gitea/repos.go

@@ -255,4 +255,3 @@ func (c *Client) GetRepo(ctx context.Context, owner, name string) (*Repo, error)
 	}
 	return &r, nil
 }
-

internal/gitea/repos_test.go

@@ -79,8 +79,8 @@ func TestCreateRepo_Org(t *testing.T) {
 
 	c := gitea.NewClient(srv.URL, "tok")
 	r, err := c.CreateRepo(context.Background(), gitea.CreateRepoArgs{
-		Name:  "infra",
-		Org:   "hyperguild",
+		Name: "infra",
+		Org:  "hyperguild",
 	})
 	require.NoError(t, err)
 	assert.Equal(t, "hyperguild/infra", r.FullName)

internal/mcp/server.go

@@ -9,7 +9,7 @@ import (
 )
 
 const (
-	ProtocolVersion    = "2025-03-26"
+	ProtocolVersion     = "2025-03-26"
 	maxRequestBodyBytes = 1 << 20 // 1 MiB
 )
 

internal/mcp/stdio_test.go

@@ -25,6 +25,7 @@ type echoTool struct{}
 func (echoTool) Descriptor() registry.ToolDescriptor {
 	return registry.ToolDescriptor{Name: "echo", Description: "echoes its input"}
 }
+
 func (echoTool) Call(_ context.Context, args json.RawMessage) (json.RawMessage, error) {
 	return args, nil
 }

internal/tools/file_write_branch_test.go

@@ -16,10 +16,12 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-const branchCheckExistsResp = `{"name":"feat/x","commit":{"id":"abc","url":"http://example.com"}}`
-const createBranchResp = `{"name":"feat/new","commit":{"id":"abc","url":"http://example.com"}}`
-const upsertFileResp = `{"content":{"path":"doc.md","sha":"filsha","html_url":"http://example.com/doc.md"},"commit":{"sha":"cmt1","html_url":"http://example.com/commit/cmt1"}}`
-const getRepoResp = `{"name":"myrepo","full_name":"owner/myrepo","default_branch":"main"}`
+const (
+	branchCheckExistsResp = `{"name":"feat/x","commit":{"id":"abc","url":"http://example.com"}}`
+	createBranchResp      = `{"name":"feat/new","commit":{"id":"abc","url":"http://example.com"}}`
+	upsertFileResp        = `{"content":{"path":"doc.md","sha":"filsha","html_url":"http://example.com/doc.md"},"commit":{"sha":"cmt1","html_url":"http://example.com/commit/cmt1"}}`
+	getRepoResp           = `{"name":"myrepo","full_name":"owner/myrepo","default_branch":"main"}`
+)
 
 func TestFileWriteBranchCreatesBranchAndFile(t *testing.T) {
 	mux := http.NewServeMux()

internal/tools/tbd_ship.go

@@ -36,7 +36,7 @@ const (
 
 func (t *TBDShip) Descriptor() registry.ToolDescriptor {
 	return registry.ToolDescriptor{
-		Name: "tbd_ship",
+		Name:        "tbd_ship",
 		Description: "Trunk-based ship of a single-file change: branch from base, write the file, open a PR, and auto-merge (squash) to base ONLY when the head commit's CI is fully green. Fails closed to PR-only (never merges) when CI is pending, red, or absent, when the base branch requires reviews, or when the merge isn't clean — returning the PR for manual handling with a reason. Set ci_timeout_seconds to poll CI to completion (default 0 = snapshot, which returns pending right after opening the PR). Returns {merged, pr_url, pr_number, ci_status, reason, branch}.",
 		InputSchema: json.RawMessage(`{
 			"type":"object",

internal/tools/workflow_run_list_test.go

@@ -52,11 +52,11 @@ func TestWorkflowRunListTool(t *testing.T) {
 			},
 		},
 		{
-			name:      "status=all is no-op",
-			input:     `{"owner":"mathias","name":"gitea-mcp","status":"all"}`,
-			notQuery:  []string{"status"},
-			respBody:  `{"total_count":0,"workflow_runs":[]}`,
-			assert:    func(t *testing.T, out string) {},
+			name:     "status=all is no-op",
+			input:    `{"owner":"mathias","name":"gitea-mcp","status":"all"}`,
+			notQuery: []string{"status"},
+			respBody: `{"total_count":0,"workflow_runs":[]}`,
+			assert:   func(t *testing.T, out string) {},
 		},
 		{
 			name:      "branch filter",