refactor(plugin): extract channel/decision parsing modules and unify channelId resolution

plugin/channel-resolver.ts

@@ -0,0 +1,73 @@
+export function extractDiscordChannelId(ctx: Record<string, unknown>, event?: Record<string, unknown>): string | undefined {
+  const candidates: unknown[] = [
+    ctx.conversationId,
+    ctx.OriginatingTo,
+    event?.to,
+    (event?.metadata as Record<string, unknown>)?.to,
+  ];
+
+  for (const c of candidates) {
+    if (typeof c !== "string" || !c.trim()) continue;
+    const s = c.trim();
+
+    if (s.startsWith("channel:")) {
+      const id = s.slice("channel:".length);
+      if (/^\d+$/.test(id)) return id;
+    }
+
+    if (s.startsWith("discord:channel:")) {
+      const id = s.slice("discord:channel:".length);
+      if (/^\d+$/.test(id)) return id;
+    }
+
+    if (/^\d{15,}$/.test(s)) return s;
+  }
+
+  return undefined;
+}
+
+export function extractDiscordChannelIdFromSessionKey(sessionKey?: string): string | undefined {
+  if (!sessionKey) return undefined;
+
+  const canonical = sessionKey.match(/discord:(?:channel|group):(\d+)/);
+  if (canonical?.[1]) return canonical[1];
+
+  const suffix = sessionKey.match(/:channel:(\d+)$/);
+  if (suffix?.[1]) return suffix[1];
+
+  return undefined;
+}
+
+export function extractUntrustedConversationInfo(text: string): Record<string, unknown> | undefined {
+  const marker = "Conversation info (untrusted metadata):";
+  const idx = text.indexOf(marker);
+  if (idx < 0) return undefined;
+  const tail = text.slice(idx + marker.length);
+  const m = tail.match(/```json\s*([\s\S]*?)\s*```/i);
+  if (!m) return undefined;
+
+  try {
+    const parsed = JSON.parse(m[1]);
+    return parsed && typeof parsed === "object" ? (parsed as Record<string, unknown>) : undefined;
+  } catch {
+    return undefined;
+  }
+}
+
+export function extractDiscordChannelIdFromConversationMetadata(conv: Record<string, unknown>): string | undefined {
+  if (typeof conv.chat_id === "string" && conv.chat_id.startsWith("channel:")) {
+    const id = conv.chat_id.slice("channel:".length);
+    if (/^\d+$/.test(id)) return id;
+  }
+
+  if (typeof conv.conversation_label === "string") {
+    const labelMatch = conv.conversation_label.match(/channel id:(\d+)/);
+    if (labelMatch?.[1]) return labelMatch[1];
+  }
+
+  if (typeof conv.channel_id === "string" && /^\d+$/.test(conv.channel_id)) {
+    return conv.channel_id;
+  }
+
+  return undefined;
+}