feat: create canonical schema and README\n\nGenerate single schema migration and add deployment guide.

DATABASE.md

@@ -0,0 +1,30 @@
+## Database Setup
+
+### Fresh deployment
+
+Run **one file**:
+
+```
+scripts/schema.sql
+```
+
+Paste it in Supabase → **SQL Editor → New query** and hit Run.  
+That is the complete, idempotent schema — all tables, enums, indexes, RLS policies, functions, and triggers.
+
+### Existing deployment
+
+The numbered scripts (`001_*` → `011_*`) are the **migration history** of the live database.  
+Do not re-run them. They are kept for reference only.
+
+### What `schema.sql` contains
+
+| Section | Contents |
+|---------|----------|
+| Extensions | `uuid-ossp` |
+| Enums | 14 custom types (`member_role`, `task_status`, etc.) |
+| Helper functions | `get_user_space_ids`, `user_has_role_in_space` |
+| Tables | `spaces`, `space_members`, `tasks`, `projects`, `payments`, `contacts`, `knowledge_base`, `secrets`, `area_leads`, `integrations`, `comms_channels`, `comms_messages`, `activity_log` |
+| Indexes | 22 performance indexes |
+| RLS policies | Full row-level security on every table |
+| Triggers | `on_space_created` (auto-creates 4 default channels) |
+| Auth hook | `on_auth_user_created` (handles create-space and join-space signup flows) |