refactor: rebrand from cs-agent to BossChat

- Rename Go module: cs-agent → bosschat
- Rename all import paths across 200+ Go files
- Rename SDK: cs-ai-agent-sdk → bosschat-sdk
- Rename message protocol: cs-agent:* → bosschat:*
- Rename JS globals: CSAgentConfig → BossChatConfig
- Rename CSS classes: cs-agent-* → bosschat-*
- Update Makefile APP_NAME and ARCHIVE_NAME
- Update logo assets
- Fix display name: BoosChat → BossChat

internal/migration/000002_init_auth_data.go

@@ -1,10 +1,10 @@
 package migration
 
 import (
-	"cs-agent/internal/models"
-	"cs-agent/internal/pkg/constants"
-	"cs-agent/internal/pkg/enums"
-	"cs-agent/internal/repositories"
+	"bosschat/internal/models"
+	"bosschat/internal/pkg/constants"
+	"bosschat/internal/pkg/enums"
+	"bosschat/internal/repositories"
 	"errors"
 	"log/slog"
 	"strings"

internal/migration/000006_backfill_conversation_customer_name.go

@@ -1,7 +1,7 @@
 package migration
 
 import (
-	"cs-agent/internal/models"
+	"bosschat/internal/models"
 
 	"github.com/mlogclub/simple/sqls"
 )

internal/migration/migration.go

@@ -1,8 +1,8 @@
 package migration
 
 import (
-	"cs-agent/internal/models"
-	"cs-agent/internal/services"
+	"bosschat/internal/models"
+	"bosschat/internal/services"
 	"errors"
 	"log/slog"
 	"sync"