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

ask/Cargo.toml

@@ -9,6 +9,7 @@ path = "src/main.rs"
 
 [dependencies]
 reqwest    = { version = "0.12", features = ["blocking", "rustls-tls", "json"], default-features = false }
+serde      = { version = "1", features = ["derive"] }
 serde_json = "1"
 duckdb     = { version = "1", features = ["bundled"] }
 dotenvy    = "0.15"