Update golangci-lint to v2.12.2 with canonical config

Bump the golangci-lint Docker image pin in Dockerfile and the
release-archive sha256 pins in script/bootstrap from 2.11.3 to
2.12.2, and replace .golangci.yml with the canonical config. The
canonical config moves lll/funlen/cyclop/dupl settings from the
top-level linters-settings key (ignored by the v2 schema) to
linters.settings, so those thresholds now actually apply.

Fix all findings the newly applied thresholds surfaced:

- lll: wrap or shorten seven over-length lines (struct tag
  comments, test logger construction, a func signature, and a
  nosec comment)
- goconst: use http.MethodPost/http.MethodPut and new shared
  constants for repeated test strings; add tmplKeyError and
  tmplKeyWebhook constants for template data keys in handlers
- dupl: merge buildHTTPTargetConfig and buildSlackTargetConfig
  into a parameterized buildURLTargetConfig; drop the duplicate
  iWebhookDB test helper in favor of testWebhookDB; extract
  shared helpers in middleware and session tests

internal/database/webhook_db_manager_test.go

@@ -2,6 +2,7 @@ package database_test
 
 import (
 	"context"
+	"net/http"
 	"os"
 	"path/filepath"
 	"testing"
@@ -25,8 +26,8 @@ func setupTestWebhookDBManager(
 	lc := fxtest.NewLifecycle(t)
 
 	g := &globals.Globals{
-		Appname: "webhooker-test",
-		Version: "test",
+		Appname: testAppname,
+		Version: testVersion,
 	}
 
 	l, err := logger.New(
@@ -83,10 +84,10 @@ func TestWebhookDBManager_CreateAndGetDB(t *testing.T) {
 	event := &database.Event{
 		WebhookID:    webhookID,
 		EntrypointID: uuid.New().String(),
-		Method:       "POST",
+		Method:       http.MethodPost,
 		Headers:      `{"Content-Type":["application/json"]}`,
 		Body:         `{"test": true}`,
-		ContentType:  "application/json",
+		ContentType:  testContentType,
 	}
 	require.NoError(t, db.Create(event).Error)
 	assert.NotEmpty(t, event.ID)
@@ -99,7 +100,7 @@ func TestWebhookDBManager_CreateAndGetDB(t *testing.T) {
 		db.First(&readEvent, "id = ?", event.ID).Error,
 	)
 	assert.Equal(t, webhookID, readEvent.WebhookID)
-	assert.Equal(t, "POST", readEvent.Method)
+	assert.Equal(t, http.MethodPost, readEvent.Method)
 	assert.Equal(t, `{"test": true}`, readEvent.Body)
 }
 
@@ -123,9 +124,9 @@ func TestWebhookDBManager_DeleteDB(t *testing.T) {
 	event := &database.Event{
 		WebhookID:    webhookID,
 		EntrypointID: uuid.New().String(),
-		Method:       "POST",
+		Method:       http.MethodPost,
 		Body:         `{"test": true}`,
-		ContentType:  "application/json",
+		ContentType:  testContentType,
 	}
 	require.NoError(t, db.Create(event).Error)
 
@@ -196,10 +197,10 @@ func seedDeliveryWorkflow(
 	event := &database.Event{
 		WebhookID:    webhookID,
 		EntrypointID: uuid.New().String(),
-		Method:       "POST",
+		Method:       http.MethodPost,
 		Headers:      `{"Content-Type":["application/json"]}`,
 		Body:         `{"payload": "test"}`,
-		ContentType:  "application/json",
+		ContentType:  testContentType,
 	}
 	require.NoError(t, db.Create(event).Error)
 
@@ -231,7 +232,7 @@ func verifyPendingDeliveries(
 	)
 	require.Len(t, pending, 1)
 	assert.Equal(t, event.ID, pending[0].EventID)
-	assert.Equal(t, "POST", pending[0].Event.Method)
+	assert.Equal(t, http.MethodPost, pending[0].Event.Method)
 }
 
 func completeDelivery(
@@ -303,16 +304,16 @@ func TestWebhookDBManager_MultipleWebhooks(t *testing.T) {
 	event1 := &database.Event{
 		WebhookID:    webhook1,
 		EntrypointID: uuid.New().String(),
-		Method:       "POST",
+		Method:       http.MethodPost,
 		Body:         `{"webhook": 1}`,
-		ContentType:  "application/json",
+		ContentType:  testContentType,
 	}
 	event2 := &database.Event{
 		WebhookID:    webhook2,
 		EntrypointID: uuid.New().String(),
-		Method:       "PUT",
+		Method:       http.MethodPut,
 		Body:         `{"webhook": 2}`,
-		ContentType:  "application/json",
+		ContentType:  testContentType,
 	}
 
 	require.NoError(t, db1.Create(event1).Error)