feat(telegram): add sticker support with vision caching

Add support for receiving and sending Telegram stickers:

Inbound:
- Receive static WEBP stickers (skip animated/video)
- Process stickers through dedicated vision call for descriptions
- Cache vision descriptions to avoid repeated API calls
- Graceful error handling for fetch failures

Outbound:
- Add sticker action to send stickers by fileId
- Add sticker-search action to find cached stickers by query
- Accept stickerId from shared schema, convert to fileId

Cache:
- Store sticker metadata (fileId, emoji, setName, description)
- Fuzzy search by description, emoji, and set name
- Persist to ~/.clawdbot/telegram/sticker-cache.json

Config:
- Single `channels.telegram.actions.sticker` option enables both
  send and search actions

🤖 AI-assisted: Built with Claude Code (claude-opus-4-5)
Testing: Fully tested - unit tests pass, live tested on dev gateway
The contributor understands and has reviewed all code changes.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/agents/tools/telegram-actions.ts

@@ -6,7 +6,9 @@ import {
   editMessageTelegram,
   reactMessageTelegram,
   sendMessageTelegram,
+  sendStickerTelegram,
 } from "../../telegram/send.js";
+import { getCacheStats, searchStickers } from "../../telegram/sticker-cache.js";
 import { resolveTelegramToken } from "../../telegram/token.js";
 import {
   resolveTelegramInlineButtonsScope,
@@ -255,5 +257,64 @@ export async function handleTelegramAction(
     });
   }
 
+  if (action === "sendSticker") {
+    if (!isActionEnabled("sticker")) {
+      throw new Error(
+        "Telegram sticker actions are disabled. Set channels.telegram.actions.sticker to true.",
+      );
+    }
+    const to = readStringParam(params, "to", { required: true });
+    const fileId = readStringParam(params, "fileId", { required: true });
+    const replyToMessageId = readNumberParam(params, "replyToMessageId", {
+      integer: true,
+    });
+    const messageThreadId = readNumberParam(params, "messageThreadId", {
+      integer: true,
+    });
+    const token = resolveTelegramToken(cfg, { accountId }).token;
+    if (!token) {
+      throw new Error(
+        "Telegram bot token missing. Set TELEGRAM_BOT_TOKEN or channels.telegram.botToken.",
+      );
+    }
+    const result = await sendStickerTelegram(to, fileId, {
+      token,
+      accountId: accountId ?? undefined,
+      replyToMessageId: replyToMessageId ?? undefined,
+      messageThreadId: messageThreadId ?? undefined,
+    });
+    return jsonResult({
+      ok: true,
+      messageId: result.messageId,
+      chatId: result.chatId,
+    });
+  }
+
+  if (action === "searchSticker") {
+    if (!isActionEnabled("sticker")) {
+      throw new Error(
+        "Telegram sticker actions are disabled. Set channels.telegram.actions.sticker to true.",
+      );
+    }
+    const query = readStringParam(params, "query", { required: true });
+    const limit = readNumberParam(params, "limit", { integer: true }) ?? 5;
+    const results = searchStickers(query, limit);
+    return jsonResult({
+      ok: true,
+      count: results.length,
+      stickers: results.map((s) => ({
+        fileId: s.fileId,
+        emoji: s.emoji,
+        description: s.description,
+        setName: s.setName,
+      })),
+    });
+  }
+
+  if (action === "stickerCacheStats") {
+    const stats = getCacheStats();
+    return jsonResult({ ok: true, ...stats });
+  }
+
   throw new Error(`Unsupported Telegram action: ${action}`);
 }