feat: add bun-fullstack agent and update skills

.agent/skills/tech-stack/elysiajs/references/lifecycle.md

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+# Lifecycle
+
+Instead of a sequential process, Elysia's request handling is divided into multiple stages called lifecycle events.
+
+It's designed to separate the process into distinct phases based on their responsibility without interfering with each others.
+
+### List of events in order
+
+1. **request** - early, global
+2. **parse** - body parsing
+3. **transform** / **derive** - mutate context pre validation
+4. **beforeHandle** / **resolve** - auth/guard logic
+5. **handler** - your business code
+6. **afterHandle** - tweak response, set headers
+7. **mapResponse** - turn anything into a proper `Response`
+8. **onError** - centralized error handling
+9. **onAfterResponse** - post response/cleanup tasks
+
+## Request (`onRequest`)
+
+Runs first for every incoming request.
+
+- Ideal for **caching, rate limiting, CORS, adding global headers**.
+- If the hook returns a value, the whole lifecycle stops and that value becomes the response.
+
+```ts
+new Elysia().onRequest(({ ip, set }) => {
+    if (blocked(ip)) return (set.status = 429)
+})
+```
+
+---
+
+## Parse (`onParse`)
+
+_Body parsing stage._
+
+- Handles `text/plain`, `application/json`, `multipart/form-data`, `application/x www-form-urlencoded` by default.
+- Use to add **custom parsers** or support extra `Content Type`s.
+
+```ts
+new Elysia().onParse(({ request, contentType }) => {
+    if (contentType === 'application/custom') return request.text()
+})
+```
+
+---
+
+## Transform (`onTransform`)
+
+_Runs **just before validation**; can mutate the request context._
+
+- Perfect for **type coercion**, trimming strings, or adding temporary fields that validation will use.
+
+```ts
+new Elysia().onTransform(({ params }) => {
+    params.id = Number(params.id)
+})
+```
+
+---
+
+## Derive
+
+_Runs along with `onTransform` **but before validation**; adds per request values to the context._
+
+- Useful for extracting info from headers, cookies, query, etc., that you want to reuse in handlers.
+
+```ts
+new Elysia().derive(({ headers }) => ({
+    bearer: headers.authorization?.replace(/^Bearer /, '')
+}))
+```
+
+---
+
+## Before Handle (`onBeforeHandle`)
+
+_Executed after validation, right before the route handler._
+
+- Great for **auth checks, permission gating, custom pre validation logic**.
+- Returning a value skips the handler.
+
+```ts
+new Elysia().get('/', () => 'hi', {
+    beforeHandle({ cookie, status }) {
+        if (!cookie.session) return status(401)
+    }
+})
+```
+
+---
+
+## Resolve
+
+_Like `derive` but runs **after validation** along "Before Handle" (so you can rely on validated data)._
+
+- Usually placed inside a `guard` because it isn't available as a local hook.
+
+```ts
+new Elysia().guard(
+    { headers: t.Object({ authorization: t.String() }) },
+    (app) =>
+        app
+            .resolve(({ headers }) => ({
+                bearer: headers.authorization.split(' ')[1]
+            }))
+            .get('/', ({ bearer }) => bearer)
+)
+```
+
+---
+
+## After Handle (`onAfterHandle`)
+
+_Runs after the handler finishes._
+
+- Can **modify response headers**, wrap the result in a `Response`, or transform the payload.
+- Returning a value **replaces** the handler’s result, but the next `afterHandle` hooks still run.
+
+```ts
+new Elysia().get('/', () => '<h1>Hello</h1>', {
+    afterHandle({ response, set }) {
+        if (isHtml(response)) {
+            set.headers['content-type'] = 'text/html; charset=utf-8'
+            return new Response(response)
+        }
+    }
+})
+```
+
+---
+
+## Map Response (`mapResponse`)
+
+_Runs right after all `afterHandle` hooks; maps **any** value to a Web standard `Response`._
+
+- Ideal for **compression, custom content type mapping, streaming**.
+
+```ts
+new Elysia().mapResponse(({ responseValue, set }) => {
+    const body =
+        typeof responseValue === 'object'
+            ? JSON.stringify(responseValue)
+            : String(responseValue ?? '')
+
+    set.headers['content-encoding'] = 'gzip'
+    return new Response(Bun.gzipSync(new TextEncoder().encode(body)), {
+        headers: {
+            'Content-Type':
+                typeof responseValue === 'object'
+                    ? 'application/json'
+                    : 'text/plain'
+        }
+    })
+})
+```
+
+---
+
+## On Error (`onError`)
+
+_Caught whenever an error bubbles up from any lifecycle stage._
+
+- Use to **customize error messages**, **handle 404**, **log**, or **retry**.
+- Must be registered **before** the routes it should protect.
+
+```ts
+new Elysia().onError(({ code, status }) => {
+    if (code === 'NOT_FOUND') return status(404, '❓ Not found')
+    return new Response('Oops', { status: 500 })
+})
+```
+
+---
+
+## After Response (`onAfterResponse`)
+
+_Runs **after** the response has been sent to the client._
+
+- Perfect for **logging, metrics, cleanup**.
+
+```ts
+new Elysia().onAfterResponse(() =>
+    console.log('✅ response sent at', Date.now())
+)
+```
+
+---
+
+## Hook Types
+
+| Type                 | Scope                             | How to add                                                |
+| -------------------- | --------------------------------- | --------------------------------------------------------- |
+| **Local Hook**       | Single route                      | Inside route options (`afterHandle`, `beforeHandle`, …) |
+| **Interceptor Hook** | Whole instance (and later routes) | `.onXxx(cb)` or `.use(plugin)`                            |
+
+> **Remember:** Hooks only affect routes **defined after** they are registered, except `onRequest` which is global because it runs before route matching.