Add SQLite persistence, per-player NPC attitude system, character creation, and combat

- Add trait-based DB layer (db.rs) with SQLite backend for easy future swapping
- Player state persisted to SQLite: stats, inventory, equipment, room position
- Returning players skip chargen and resume where they left off
- Replace boolean hostile flag with 5-tier attitude system (friendly/neutral/wary/aggressive/hostile)
- Per-player NPC attitudes stored in DB, shift on kills with faction propagation
- Add character creation flow (chargen.rs) with data-driven races and classes from TOML
- Add turn-based combat system (combat.rs) with XP, leveling, and NPC respawn
- Add commands: take, drop, inventory, equip, use, examine, talk, attack, flee, stats
- Add world data: 5 races, 4 classes, hostile NPCs (rat, thief), new items

Made-with: Cursor

Cargo.toml

@@ -7,6 +7,8 @@ edition = "2021"
 russh = { version = "0.54", default-features = false, features = ["ring"] }
 tokio = { version = "1", features = ["full"] }
 serde = { version = "1", features = ["derive"] }
+serde_json = "1"
 toml = "0.8"
+rusqlite = { version = "0.35", features = ["bundled"] }
 log = "0.4"
 env_logger = "0.11"