chore: bump Dialectic.Backend + add Dialectic.OpenclawPlugin submodule

- Dialectic.Backend e049b1c → 5cf4302
    drop announce.go / topic.announce_* columns / ticker broadcast /
    config FabricSystemAPIKey. Backend is now pure data + state-machine;
    no Fabric coupling.
  - Dialectic.OpenclawPlugin (new submodule, pinned at 3ce5439)
    drop announce_* params from dialectic_propose_topic. New plugin
    work landed pre-bump: dialectic_list_arguments + topic_detail
    camps inline + install.mjs + ESM-clean tsconfig + .gitignore
    artifacts.

Both pair with Fabric umbrella bump f3c472e (Center/Guild/Plugin) and
ClawSkills@ba48a67 (participate-debate rewrite + analyze-intel step 4
+ rotate-fabric-system-key delete + provision-announce-channel cleanup).

.gitmodules

@@ -3,4 +3,7 @@
     url = https://git.hangman-lab.top/hzhang/Dialectic.Backend.git
 [submodule "Dialectic.Frontend"]
     path = Dialectic.Frontend
-    url = https://git.hangman-lab.top/hzhang/Dialectic.Frontend.git
+    url = https://git.hangman-lab.top/hzhang/Dialectic.Frontend.git
+[submodule "Dialectic.OpenclawPlugin"]
+	path = Dialectic.OpenclawPlugin
+	url = https://git.hangman-lab.top/hzhang/Dialectic.OpenclawPlugin.git