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>

crates/colony/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "colony"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+colony-types = { path = "../colony-types" }
+serde = { workspace = true }
+serde_json = { workspace = true }
+uuid = { workspace = true }
+chrono = { workspace = true }
+tokio = { workspace = true }
+sqlx = { workspace = true }
+axum = { workspace = true }
+tower-http = { workspace = true }
+thiserror = { workspace = true }