Add LINE channel adapter with webhook ingress and gating

src/config/schema.ts

@@ -503,6 +503,14 @@ const bluebubblesSchema = z.object({
   mention_name: z.string().default('flynn'),
 }).optional();
 
+const lineSchema = z.object({
+  channel_access_token: z.string().min(1, 'LINE channel_access_token is required'),
+  channel_secret: z.string().min(1, 'LINE channel_secret is required'),
+  allowed_source_ids: z.array(z.string()).default([]),
+  require_mention: z.boolean().default(true),
+  mention_name: z.string().default('flynn'),
+}).optional();
+
 const browserSchema = z.object({
   enabled: z.boolean().default(false),
   executable_path: z.string().optional(),
@@ -682,6 +690,7 @@ export const configSchema = z.object({
   teams: teamsSchema,
   google_chat: googleChatSchema,
   bluebubbles: bluebubblesSchema,
+  line: lineSchema,
   server: serverSchema.default({}),
   models: modelsSchema,
   backends: backendsSchema.default({}),