feat: rewrite as moderation bot (#11)

## Summary

- Replaces the old AI companion bot with a full Discord moderation system
- Adds 8 slash commands: `warn`, `mute`, `unmute`, `kick`, `softban`, `ban`, `unban`, `prune`
- Adds logging for member join/leave, activity (messages, threads, voice), and moderation actions
- Audit log integration captures manual bans, kicks, timeouts, and unbans
- All applicable actions post sanctions to the Hikari sanction API
- All commands are ephemeral, use Components v2, and enforce permission + role hierarchy checks

## Test plan

- [ ] Run `pnpm register` to register all 8 commands to the guild
- [ ] Verify each command appears in Discord and is only visible to members with the appropriate permissions
- [ ] Test each command against a valid target and confirm mod log entry, DM notification, and sanction record
- [ ] Test each command against an invalid target (equal/higher role, self, bot) and confirm correct error response
- [ ] Perform a manual ban, kick, and timeout in the Discord UI and confirm audit log handler picks them up
- [ ] Perform a manual unban and confirm it logs correctly without creating a sanction
- [ ] Verify join/leave messages appear in the welcome log channel
- [ ] Verify message edits, deletes, thread events, and voice state changes appear in the activity log channel

✨ This issue was created with help from Hikari~ 🌸

Reviewed-on: #11
Co-authored-by: Hikari <hikari@nhcarrigan.com>
Co-committed-by: Hikari <hikari@nhcarrigan.com>

package.json

@@ -1,13 +1,14 @@
 {
   "name": "keiko",
   "version": "1.0.0",
-  "description": "Naomi's personal AI assistant.",
+  "description": "Naomi's community moderation bot.",
   "main": "index.js",
   "type": "module",
   "scripts": {
     "build": "rm -rf prod && tsc",
     "lint": "eslint src --max-warnings 0",
-    "start": "op run --env-file=prod.env --no-masking -- node prod/index.js",
+    "register": "op run --env-file=prod.env --no-masking -- node prod/src/register.js",
+    "start": "op run --env-file=prod.env --no-masking -- node prod/src/index.js",
     "test": "echo \"No tests yet!\" && exit 0"
   },
   "keywords": [],
@@ -17,16 +18,13 @@
     "@nhcarrigan/eslint-config": "5.2.0",
     "@nhcarrigan/typescript-config": "4.0.0",
     "@types/node": "24.7.1",
-    "@vitest/coverage-istanbul": "3.2.4",
+    "@vitest/coverage-v8": "3.2.4",
     "eslint": "9.37.0",
     "typescript": "5.9.3",
     "vitest": "3.2.4"
   },
   "dependencies": {
-    "@anthropic-ai/sdk": "0.74.0",
-    "@nhcarrigan/discord-analytics": "0.0.6",
     "@nhcarrigan/logger": "1.1.1",
-    "discord.js": "14.25.1",
-    "fastify": "5.6.1"
+    "discord.js": "14.25.1"
   }
 }