refactor: delete stale files and consolidate .mindmodel structure

Deleted stale root-level Python files:
- main.py (unused 'Hello world' script)
- verify.py (unused table info script)
- scraper.py (unused MotionScraper class)
- scheduler.py (unused DataUpdateScheduler class)

Deleted duplicate .mindmodel root YAML files (subdirectory versions are more comprehensive):
- anti-patterns.yaml, architecture.yaml, conventions.yaml
- dependencies.yaml, domain.yaml, domain-glossary.yaml
- stack.yaml, tech-stack.yaml, workflows.yaml

Added comprehensive .mindmodel subdirectories:
- constraints/ (naming, db-schema, error-handling, types, etc.)
- patterns/ (api, architecture, database, python, streamlit, etc.)
- examples/ (code examples for each pattern)
- anti-patterns/, architecture/, conventions/, dependencies/, domain/, stack/

Updated ARCHITECTURE.md to reflect current codebase:
- Removed references to non-existent files
- Added missing files (explorer.py, explorer_helpers.py, pipeline/)
- Added directory structure documentation
- Updated tech stack to include scipy, sklearn, umap

Updated .gitignore:
- Added patterns for generated analysis files
- Added .worktrees/ pattern (was already in gitignore but dir was deleted)

Removed empty .worktrees/ directory

.mindmodel/dependencies/dependencies.yaml

@@ -0,0 +1,78 @@
+# Dependencies
+
+## Core Library Wiring
+
+### Database Layer
+```
+ibis → DuckDB → MotionDatabase singleton (database.py)
+         ↑
+    sqlglot (ibis dependency)
+```
+
+### Data Processing
+```
+pandas → (used throughout for DataFrame operations)
+numpy → (used by sklearn, scipy, umap)
+scipy → spatial.procrustes for window alignment
+```
+
+### ML Pipeline
+```
+sklearn.cluster → KMeans, Procrustes
+sklearn.preprocessing → StandardScaler
+umap → UMAP (optional, graceful fallback)
+```
+
+### Visualization
+```
+plotly → explorer_helpers.py chart builders
+st.plotly_chart → explorer.py rendering
+```
+
+### Streamlit
+```
+streamlit → all pages, @st.cache_data decorators
+```
+
+## Optional Dependencies
+| Package | Required | Fallback |
+|---------|----------|----------|
+| `umap` | No | Use raw SVD vectors (first 2 dims) |
+| `plotly` | Yes | Raises ImportError |
+| `duckdb` | Yes | — |
+| `ibis` | Yes | — |
+| `sklearn` | Yes | — |
+
+## Singleton Instances
+| Module | Instance | Type |
+|--------|----------|------|
+| `database.py` | `db` | `MotionDatabase` |
+| `config.py` | `config` | `Config` (dataclass) |
+| `config.py` | `PARTY_COLOURS` | `dict[str, str]` |
+
+## Key Imports by File
+```
+explorer.py:
+  - import streamlit as st
+  - from database import db
+  - from explorer_helpers import *
+
+explorer_helpers.py:
+  - import pandas as pd
+  - import plotly.graph_objects as go
+  - from database import db (optional, for type hints)
+
+database.py:
+  - import ibis
+  - import duckdb
+  - from config import config, PARTY_COLOURS
+
+config.py:
+  - from dataclasses import dataclass, field
+  - import streamlit as st (optional, for warnings)
+```
+
+## Environment
+- Python ≥3.13
+- Environment variables via `.env` (DB path, API keys)
+- No `.env` values in constraint files (security)