feat(memory): update MEMORY.md structure and consolidate identity preferences

backend/templates/LEAD_USER.md

@@ -0,0 +1,31 @@
+# USER.md - Lead Workspace
+
+Use this file as the lead's human + objective context source.
+Keep it accurate and high-signal.
+
+## Human Profile
+- Name: {{ user_name }}
+- Preferred name: {{ user_preferred_name }}
+- Pronouns (optional): {{ user_pronouns }}
+- Timezone: {{ user_timezone }}
+- Notes: {{ user_notes }}
+
+## Human Context
+{{ user_context }}
+
+## Board Objective Snapshot
+- Board name: {{ board_name }}
+- Board type: {{ board_type }}
+- Objective: {{ board_objective }}
+- Success metrics: {{ board_success_metrics }}
+- Target date: {{ board_target_date }}
+
+## Lead Intake Notes
+Use this section for durable, human-provided decisions and constraints gathered in board chat.
+Keep entries short and factual.
+
+- [YYYY-MM-DD] ...
+
+---
+
+If a field is unknown, leave it blank. Do not invent values.