✨ Identity onboarding + Verbatim dialogue memory

- Added [identity] config section (agent_name, agent_role, user_name,
  user_role, setup_complete) to GyandootConfig and AgentConfig
- Agent loop now injects identity into system prompt on startup
- Agent loop injects past verbatim dialogue memory into system prompt
- Added dialogue_append() / dialogue_read() to MemPalace
  - Word-by-word, line-by-line verbatim record in dialogue.md
  - No compression, no truncation — every message preserved
- Agent loop writes to BOTH daily transcript AND verbatim dialogue
  on every turn
- All config paths pass identity through (flat converter, subagents)

crates/gyandoot-subagents/src/lib.rs

@@ -268,6 +268,7 @@ impl SubAgentWorker {
             security: gyandoot_core::SecurityRootConfig::default(),
             kanban: gyandoot_core::KanbanRootConfig::default(),
             skills: gyandoot_core::SkillsRootConfig::default(),
+            identity: gyandoot_core::IdentitySection::default(),
         };
 
         // Try to create the agent loop. If the provider config isn't viable