docs(claude): add uv workspace management + data modeling patterns

- uv workspace section: sync all-packages, add deps, create new source package
- Data modeling patterns: foundation-as-ontology (dim_venues, dim_cities
  conform cross-source identifiers); extraction pattern notes (state SQLite)

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

.claude/CLAUDE.md

@@ -59,7 +59,7 @@ ruff format .
 uv run pytest tests/ -v
 
 # Dev server
-./scripts/dev_run.sh
+make dev
 
 # Extract data
 LANDING_DIR=data/landing uv run extract
@@ -152,6 +152,37 @@ All env vars are defined in the sops files. See `.env.dev.sops` for the full lis
 | `RESEND_WEBHOOK_SECRET` | `""` | Resend webhook signature secret (skip verification if empty) |
 
 
+## uv workspace management
+
+```bash
+# Install everything (run from repo root)
+uv sync --all-packages --all-groups
+
+# Add a dependency to an existing package
+uv add --package padelnomics <package>
+uv add --package padelnomics-web duckdb
+
+# Add a new extraction package (if splitting extract further)
+uv init --package extract/new_source
+uv add --package new_source padelnomics-extract niquests
+# Then add to [tool.uv.workspace] members in pyproject.toml
+```
+
+Always use `uv` CLI to manage dependencies — never edit `pyproject.toml` manually for dependency changes.
+
+## Data modeling patterns
+
+**Foundation layer is the ontology.** Dimension tables conform identifiers across all data sources:
+- `dim_venues` maps Overpass, Playtomic, and other source identifiers to a single row per venue
+- `dim_cities` conforms city/municipality identifiers across Eurostat, Overpass, and geocoding results
+- New data sources add columns to existing dims, not new tables
+- Facts join to dims via surrogate keys (MD5 hash keys generated in staging)
+
+**Extraction pattern:**
+- State tracked in SQLite (`{LANDING_DIR}/.state.sqlite`, WAL mode) — not DuckDB; it's OLTP
+- Landing zone is immutable and content-addressed: `{LANDING_DIR}/{source}/{partitions}/{hash}.ext`
+- Adding a new source: create package, add to workflows.toml, add staging + foundation models
+
 ## Coding philosophy
 
 - **Simple and procedural** — functions over classes, no "Manager" patterns