refactor: reorganize project structure and fix broken references

- Move scripts to scripts/ directory (roda.sh, prepara_db.py, etc.)
- Move shell config to shell/ directory (Caddyfile, auth.py, haloy.yml)
- Move basedosdados.duckdb to data/ directory
- Update Dockerfile and start.sh with new file paths
- Update README.md with correct script paths
- Remove Python ask.py (replaced by Rust binary in ask/ask)
- Add Rust source files (schema_filter.rs, sql_generator.rs, table_selector.rs)
- Remove sentence-transformer dependencies from ask
- Move docs and context artifacts to their directories

shell/haloy.yml

@@ -0,0 +1,31 @@
+name: basedosdados
+server: haloy.xn--2dk.xyz
+api_token:
+  from:
+    env: HALOY_TOKEN
+domains:
+  - domain: db.xn--2dk.xyz
+    port: 8080
+    health_check_path: /health
+  - domain: ask.xn--2dk.xyz
+    port: 8080
+    health_check_path: /health
+env:
+  - name: GEMINI_API_KEY
+    from:
+      env: GEMINI_API_KEY
+  - name: HETZNER_S3_ENDPOINT
+    from:
+      env: HETZNER_S3_ENDPOINT
+  - name: AWS_ACCESS_KEY_ID
+    from:
+      env: AWS_ACCESS_KEY_ID
+  - name: AWS_SECRET_ACCESS_KEY
+    from:
+      env: AWS_SECRET_ACCESS_KEY
+  - name: BASIC_AUTH_PASSWORD
+    from:
+      env: BASIC_AUTH_PASSWORD
+  - name: BUCKET_REGION
+    from:
+      env: BUCKET_REGION