S1: Colony backend skeleton — Axum + SQLite, channels + messages CRUD

Monorepo structure:
- crates/colony-types: API types (serde + ts-rs), separate from DB models
- crates/colony: Axum server, SQLite via sqlx, migrations

Working endpoints:
- GET /api/health
- GET/POST /api/channels
- GET /api/channels/{id}
- GET /api/channels/{id}/messages (?since=, ?type=, ?user_id=)
- POST /api/channels/{id}/messages (with type + metadata)

Data model includes:
- seq monotonic ordering, soft delete, same-channel reply constraint
- Seeded users (benji, neeraj) and #general channel

Also: codex-review skill, .gitignore

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Cargo.toml

@@ -0,0 +1,15 @@
+[workspace]
+members = ["crates/*"]
+resolver = "2"
+
+[workspace.dependencies]
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"
+uuid = { version = "1", features = ["v4", "serde"] }
+chrono = { version = "0.4", features = ["serde"] }
+tokio = { version = "1", features = ["full"] }
+sqlx = { version = "0.8", features = ["runtime-tokio", "sqlite", "chrono", "uuid"] }
+axum = { version = "0.8", features = ["ws"] }
+tower-http = { version = "0.6", features = ["cors", "fs"] }
+ts-rs = { version = "10", features = ["serde-json-impl", "uuid-impl", "chrono-impl"] }
+thiserror = "2"