Remove hardcoded sidechat UUIDs from dm.py (heartbeat, 646-opm-work)

Thread UUIDs rotate -- heartbeat-opm died twice in one day
(5bd5b350 -> 0077e918 -> dead), dropping self_main_loop digests.
SIDCHAT_ALIASES is now intentionally empty; targets fall through to
job-sidechats.json dynamic mappings then name-based sidechat use with
autoprovision, which self-heals. Also removed stale heartbeat-opm and
pipe-9735f2 entries (dead UUID 0077e918) from job-sidechats.json.

Test: dm.py send to heartbeat resolved via name and SENT+VERIFIED
(thread 5f18476d-8994-49e7-a9e0-4838732363fe).

Session: sidechat/chromebox-ops

bin/dm.py

@@ -205,15 +205,19 @@ LOG_FILE = "/home/super/Projects/NetVM/dm-log.jsonl"
 # These bypass fuzzy name matching for reliable placement.
 # Resolved 2026-10-04. Add new entries as sidechats are created.
 SIDCHAT_ALIASES = {
-    "646-opm-work": "d410b9ad-f667-465f-a103-43fabc0f69fe",
-    "heartbeat": "0077e918-9ac8-40ba-b0ad-65f9f78037c4",  # dedicated heartbeat sidechat (was colliding with 646 tasks)
+    # Intentionally empty. Thread UUIDs rotate (heartbeat-opm died twice in
+    # one day: 5bd5b350 -> 0077e918 -> dead). Hardcoded UUIDs misdeliver or
+    # drop. Targets fall through to job-sidechats.json dynamic mappings,
+    # then name-based `sidechat use` with autoprovision, which self-heals.
+    # Do NOT add hardcoded UUIDs here.
 }
-# NOTE 2026-10-04: "646 tasks" alias REMOVED -- the hardcoded UUID
-# 1e75a740-d08f-443d-a0f9-793db196e24f is stale (not a valid thread on 646's
-# account; the SPA redirects to another thread, causing misdelivery).
-# "646 tasks" now falls through to passthrough -> fuzzy name search ->
+# NOTE 2026-10-04: "646 tasks", "heartbeat", and "646-opm-work" aliases
+# REMOVED -- all hardcoded UUIDs (1e75a740-..., 0077e918-..., d410b9ad-...)
+# went stale (threads rotate; the SPA redirects to another thread, causing
+# misdelivery or dropped digests). Targets now fall through to passthrough
+# -> job-sidechats.json dynamic mapping -> fuzzy name search ->
 # autoprovision, which registers the live UUID in job-sidechats.json.
-# Do NOT re-add a hardcoded UUID here; use job-sidechats.json instead.
+# Do NOT re-add hardcoded UUIDs here; use job-sidechats.json instead.
 
 def resolve_sidechat_target(target):
     """Resolve target alias or name to UUID dynamically from job-sidechats.json."""

job-sidechats.json

@@ -1,5 +1,4 @@
 {
-  "heartbeat-opm": "0077e918-9ac8-40ba-b0ad-65f9f78037c4",
   "646-pip-coord": {
     "thread_uuid": "4466d0c1-7961-4cf3-b99d-1ab7c38484c2",
     "agent": "pip"
@@ -18,11 +17,6 @@
     "agent": "opm",
     "created_at": "2026-10-04T16:39:34.721269+00:00"
   },
-  "pipe-9735f2": {
-    "thread_uuid": "0077e918-9ac8-40ba-b0ad-65f9f78037c4",
-    "agent": "opm",
-    "created_at": "2026-10-04T16:43:03.587214+00:00"
-  },
   "pipe-7d2896": {
     "thread_uuid": "78e03d7a-0ba2-440e-a730-6f3b3737cbac",
     "agent": "opm",