fix: use common.Marshal/Unmarshal per Rule 1 + telegram null safety

- model/user.go: replace json.Unmarshal/Marshal with common.* wrapper
  functions as required by project Rule 1 (3 occurrences)
- relay/channel/claude/relay-claude.go: replace 3 json.* calls with
  common.* (tool call args unmarshal, response marshal)
- relay/channel/gemini/relay-gemini.go: replace 5 json.* calls with
  common.* (content parsing, function args, response marshal)
- adapters/telegram/index.ts: add optional chaining on callback query
  message.chat.id and null coalescing on message.text to prevent crash
  when callback message is undefined

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

cc-haha/adapters/telegram/index.ts

@@ -718,7 +718,7 @@ bot.on('callback_query:data', async (ctx) => {
 
   const requestId = parts[1]!
   const allowed = parts[2] === 'yes'
-  const chatId = String(ctx.callbackQuery.message?.chat.id)
+  const chatId = String(ctx.callbackQuery.message?.chat?.id)
 
   bridge.sendPermissionResponse(chatId, requestId, allowed)
   const runtime = getRuntimeState(chatId)
@@ -727,7 +727,7 @@ bot.on('callback_query:data', async (ctx) => {
   const statusText = allowed ? '✅ 已允许' : '❌ 已拒绝'
   try {
     await ctx.editMessageText(
-      ctx.callbackQuery.message?.text + `\n\n${statusText}`,
+      (ctx.callbackQuery.message?.text ?? '') + `\n\n${statusText}`,
     )
   } catch { /* ignore */ }