ci: add Gitea Actions workflow with gofmt and test jobs

Add CI workflow at .gitea/workflows/ci.yml triggered on pull_request
with two jobs: fmt (gofmt check) and test (go test ./...).

Fix gofmt issues (import ordering) in 7 files so CI passes from
the start.

Fixes #7

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

internal/database/models.go

@@ -6,28 +6,28 @@ import (
 
 // Task status constants matching the requirement's state machine.
 const (
-	StatusIgnored       = "IGNORED"
-	StatusReceived      = "RECEIVED"
-	StatusAIProcessing  = "AI_PROCESSING"
-	StatusCallbackDone  = "CALLBACK_DONE"
-	StatusSMTPRetrying  = "SMTP_RETRYING"
-	StatusCompleted     = "COMPLETED"
-	StatusFailed        = "FAILED"
+	StatusIgnored      = "IGNORED"
+	StatusReceived     = "RECEIVED"
+	StatusAIProcessing = "AI_PROCESSING"
+	StatusCallbackDone = "CALLBACK_DONE"
+	StatusSMTPRetrying = "SMTP_RETRYING"
+	StatusCompleted    = "COMPLETED"
+	StatusFailed       = "FAILED"
 )
 
 // Task represents a single email processing unit tracked through the pipeline.
 type Task struct {
-	ID              uint       `gorm:"primaryKey;autoIncrement"`
-	TaskUUID        string     `gorm:"uniqueIndex;not null"`
-	ThreadID        string     `gorm:"index"`
-	MessageID       string     `gorm:"index"`
+	ID              uint   `gorm:"primaryKey;autoIncrement"`
+	TaskUUID        string `gorm:"uniqueIndex;not null"`
+	ThreadID        string `gorm:"index"`
+	MessageID       string `gorm:"index"`
 	Sender          string
 	Subject         string
 	BodyPlain       string
 	AIResponse      string
-	Status          string     `gorm:"index;not null"`
-	AttemptOpenClaw int        `gorm:"default:0"`
-	AttemptSMTP     int        `gorm:"default:0"`
+	Status          string `gorm:"index;not null"`
+	AttemptOpenClaw int    `gorm:"default:0"`
+	AttemptSMTP     int    `gorm:"default:0"`
 	LastError       *string
 	NextRetryAt     *time.Time
 	CreatedAt       time.Time