refactor: cursor-agent uses runtime.extract for workspace detection

- Remove llmProvider and workspace from CursorAgentConfig (now just command/model/timeout)
- extractWorkspacePath uses runtime.extract + runtime.cas instead of standalone reactor
- TextProducerFn signature gains runtime parameter: (ctx, prompt, runtime)
- develop-entry.ts hardcodes cursor-agent path, no more env var dependency
- Drop @uncaged/workflow-reactor dep from workflow-agent-cursor
- Update tests for simplified config

小橘 <xiaoju@shazhou.work>

biome.json

@@ -1,5 +1,5 @@
 {
-  "$schema": "https://biomejs.dev/schemas/2.4.14/schema.json",
+  "$schema": "https://biomejs.dev/schemas/2.4.15/schema.json",
   "files": {
     "includes": ["**", "!**/dist", "!**/node_modules", "!packages/workflow/workflow"]
   },