tools(relay): durable JSONL message log + pm wrapper + 120-char preview

- queue.ts: append every posted message to relay-log.jsonl (full body,
  survives the consume-once drain + restarts). gitignored.
- server.ts: bump the stdout preview from 60 to 120 chars.
- tools/relay/pm: absolute-path bash wrapper (read|pending|send) so relay
  ops work from any cwd without cd or hand-built JSON escaping.
- Fold in Dev-C's Phase 6 ARCHITECTURE.md slice as a coordination artifact.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tools/relay/queue.ts

@@ -1,4 +1,13 @@
 import { randomUUID } from "node:crypto";
+import { appendFileSync } from "node:fs";
+import { fileURLToPath } from "node:url";
+import { dirname, join } from "node:path";
+
+// Append-only archive of every posted message. The in-memory queues are
+// consume-once (read() drains the inbox) and vanish on restart, so this is
+// the only durable, full-body record of relay traffic. One JSON object per
+// line; never truncated.
+const LOG_PATH = join(dirname(fileURLToPath(import.meta.url)), "relay-log.jsonl");
 
 export type Role = "pm" | "dev-a" | "dev-b" | "dev-c" | "dev-d" | "dev-e" | "dev-f";
 export type MessageKind = "status" | "question" | "directive" | "free";
@@ -39,6 +48,11 @@ export class RelayQueue {
       ts: new Date().toISOString(),
     };
     this.queues.get(to)!.push(msg);
+    try {
+      appendFileSync(LOG_PATH, JSON.stringify(msg) + "\n");
+    } catch {
+      // Logging is best-effort; never let a disk error drop a message.
+    }
     return msg;
   }