docs: replace implementation plans with architecture and API reference docs

Remove phase implementation plans, design notes, and source spreadsheet
that are no longer needed. Add architecture.md, API_REFERENCE.md, and
database_schema.md for ongoing development and debugging reference.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/CLAUDE.md

@@ -1,6 +1,6 @@
-# Documentation Folder
+# Documentation
 
-This folder contains business planning, architecture decisions, and documentation.
+This folder contains architecture, API reference, and development documentation.
 
 **No application code belongs here.**
 
@@ -8,15 +8,16 @@ This folder contains business planning, architecture decisions, and documentatio
 
 | Document | Purpose |
 |----------|---------|
-| `code_guidelines.md` | Code creation guidelines and Git strategy |
-| `security.md` | Python focused security code suggestions |
-| `roadmap.md` | 5-phase development roadmap |
-| `plans/` | Design documents and implementation plans |
-
+| `architecture.md` | App architecture, layers, patterns, request lifecycle |
+| `API_REFERENCE.md` | All 23 endpoints with params, auth, and response details |
+| `database_schema.md` | All 8 tables, columns, relationships, migrations |
+| `code_guidelines.md` | Coding standards and Git strategy |
+| `security.md` | Python-focused security guidance |
+| `roadmap.md` | Feature status and future plans |
 
 ## Guidelines
 
 - Keep documents focused and concise
 - Update docs when architecture decisions change
 - Use markdown tables for structured information
-- Include links to external documentation where relevant
+- Include links to external documentation where relevant