feat(channels): add signal-cli channel adapter

src/config/schema.ts

@@ -400,6 +400,17 @@ const matrixSchema = z.object({
   display_name: z.string().optional(),
 }).optional();
 
+const signalSchema = z.object({
+  account: z.string().min(1, 'Signal account is required'),
+  signal_cli_path: z.string().default('signal-cli'),
+  allowed_numbers: z.array(z.string()).default([]),
+  allowed_group_ids: z.array(z.string()).default([]),
+  require_mention: z.boolean().default(true),
+  mention_name: z.string().default('flynn'),
+  poll_interval_ms: z.number().min(1000).max(60000).default(5000),
+  send_timeout_ms: z.number().min(1000).max(60000).default(15000),
+}).optional();
+
 const browserSchema = z.object({
   enabled: z.boolean().default(false),
   executable_path: z.string().optional(),
@@ -566,6 +577,7 @@ export const configSchema = z.object({
   slack: slackSchema,
   whatsapp: whatsappSchema,
   matrix: matrixSchema,
+  signal: signalSchema,
   server: serverSchema.default({}),
   models: modelsSchema,
   backends: backendsSchema.default({}),
@@ -610,6 +622,7 @@ export type DiscordConfig = z.infer<typeof discordSchema>;
 export type SlackConfig = z.infer<typeof slackSchema>;
 export type WhatsAppConfig = z.infer<typeof whatsappSchema>;
 export type MatrixConfig = z.infer<typeof matrixSchema>;
+export type SignalConfig = z.infer<typeof signalSchema>;
 export type RetryPolicyConfig = z.infer<typeof retrySchema>;
 export type ContextLevel = z.infer<typeof contextLevelSchema>;
 export type PromptConfig = z.infer<typeof promptSchema>;