fix: pin @opencode-ai/sdk to <1.2.7 to fix broken v2 exports

@opencode-ai/sdk versions 1.2.7+ have a broken build where dist/v2/
directory is missing (files are incorrectly placed under dist/src/v2/
instead). This causes 'Cannot find module' errors when running takt
installed via npm install -g.

The v2 export path '@opencode-ai/sdk/v2' resolves to dist/v2/index.js
per the package's exports map, but that file does not exist in 1.2.7+.

Pinning to <1.2.7 as a workaround until the SDK package is fixed.

package.json

@@ -62,7 +62,7 @@
   "dependencies": {
     "@anthropic-ai/claude-agent-sdk": "^0.2.47",
     "@openai/codex-sdk": "^0.103.0",
-    "@opencode-ai/sdk": "^1.1.53",
+    "@opencode-ai/sdk": ">=1.1.53 <1.2.7",
     "chalk": "^5.3.0",
     "commander": "^12.1.0",
     "update-notifier": "^7.3.1",