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/migrations/001_init.sql

@@ -0,0 +1,75 @@
+CREATE TABLE IF NOT EXISTS users (
+    id TEXT PRIMARY KEY NOT NULL,
+    username TEXT UNIQUE NOT NULL,
+    display_name TEXT NOT NULL,
+    role TEXT NOT NULL CHECK (role IN ('ape', 'agent')),
+    password_hash TEXT,
+    created_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%SZ', 'now'))
+);
+
+CREATE TABLE IF NOT EXISTS api_tokens (
+    id TEXT PRIMARY KEY NOT NULL,
+    user_id TEXT NOT NULL REFERENCES users(id),
+    token_hash TEXT UNIQUE NOT NULL,
+    token_prefix TEXT NOT NULL,
+    name TEXT NOT NULL,
+    created_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%SZ', 'now'))
+);
+
+CREATE TABLE IF NOT EXISTS channels (
+    id TEXT PRIMARY KEY NOT NULL,
+    name TEXT UNIQUE NOT NULL,
+    description TEXT NOT NULL DEFAULT '',
+    created_by TEXT NOT NULL REFERENCES users(id),
+    created_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%SZ', 'now'))
+);
+
+CREATE TABLE IF NOT EXISTS messages (
+    id TEXT PRIMARY KEY NOT NULL,
+    seq INTEGER NOT NULL,
+    channel_id TEXT NOT NULL REFERENCES channels(id),
+    user_id TEXT NOT NULL REFERENCES users(id),
+    type TEXT NOT NULL CHECK (type IN ('text', 'code', 'result', 'error', 'plan')),
+    content TEXT NOT NULL,
+    metadata TEXT,
+    reply_to TEXT REFERENCES messages(id),
+    created_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%SZ', 'now')),
+    updated_at TEXT,
+    deleted_at TEXT
+);
+
+CREATE INDEX IF NOT EXISTS idx_messages_channel ON messages(channel_id, seq);
+CREATE INDEX IF NOT EXISTS idx_messages_created ON messages(channel_id, created_at);
+
+-- Auto-increment seq per channel using a trigger
+CREATE TABLE IF NOT EXISTS channel_seq (
+    channel_id TEXT PRIMARY KEY NOT NULL REFERENCES channels(id),
+    next_seq INTEGER NOT NULL DEFAULT 1
+);
+
+CREATE TRIGGER IF NOT EXISTS trg_message_seq
+AFTER INSERT ON messages
+BEGIN
+    INSERT INTO channel_seq (channel_id, next_seq) VALUES (NEW.channel_id, 2)
+    ON CONFLICT(channel_id) DO UPDATE SET next_seq = next_seq + 1;
+END;
+
+-- Enforce reply_to same-channel constraint
+CREATE TRIGGER IF NOT EXISTS trg_reply_same_channel
+BEFORE INSERT ON messages
+WHEN NEW.reply_to IS NOT NULL
+BEGIN
+    SELECT RAISE(ABORT, 'reply_to must reference a message in the same channel')
+    WHERE (SELECT channel_id FROM messages WHERE id = NEW.reply_to) != NEW.channel_id;
+END;
+
+-- Seed user for development (no auth yet)
+INSERT OR IGNORE INTO users (id, username, display_name, role)
+VALUES ('00000000-0000-0000-0000-000000000001', 'benji', 'Benji', 'ape');
+
+INSERT OR IGNORE INTO users (id, username, display_name, role)
+VALUES ('00000000-0000-0000-0000-000000000002', 'neeraj', 'Neeraj', 'ape');
+
+-- Seed a general channel
+INSERT OR IGNORE INTO channels (id, name, description, created_by)
+VALUES ('00000000-0000-0000-0000-000000000010', 'general', 'General discussion', '00000000-0000-0000-0000-000000000001');