feat: upgrade to AI SDK v6 beta and Zod v4 to fix tool schema errors

OpenAI was rejecting tool definitions with error "schema must be a JSON Schema of 'type: "object"'". This was caused by AI SDK v5 not properly converting Zod schemas to JSON Schema format.

**Changes:**
- Upgrade AI SDK from v5.0.104 to v6.0.0-beta.124
- Upgrade @ai-sdk/openai from v2.0.74 to v3.0.0-beta.22
- Upgrade Zod from v3.25.76 to v4.1.13 across all packages

**AI SDK v6 breaking changes:**
- Tool definition API: `parameters` renamed to `inputSchema`
- Removed `aiTool()` wrapper - use plain object with description, inputSchema, execute
- Streaming API: Use `textStream` async iterator instead of onChunk callback
- Zod schemas now properly converted to JSON Schema for OpenAI

**Zod v4 breaking changes:**
- `z.record()` now requires two arguments: `z.record(keySchema, valueSchema)`
- `z.enum()` params changed: `errorMap` removed, use `message` instead
- Type system improvements require explicit type parameters
- Fixed type errors in @tpmjs/env, @tpmjs/npm-client, @tpmjs/types

**Files changed:**
- apps/web/src/lib/ai-agent/tool-executor-agent.ts
  - Updated tool definition to use `inputSchema` instead of `parameters`
  - Removed `aiTool()` wrapper
  - Fixed streaming to use `textStream` iterator
- packages/env/src/index.ts
  - Updated type constraint from `z.ZodRawShape` to `Record<string, z.ZodTypeAny>`
- packages/npm-client/src/package.ts
  - Fixed `z.record()` calls to include both key and value schemas
  - Added type assertions for record indexing
- packages/types/src/tpmjs.ts
  - Changed `errorMap` to `message` in z.enum() calls

**Testing:**
- ✅ Type-check passes
- ✅ Production build succeeds
- ✅ All routes compile correctly

This fixes the tool execution error where OpenAI rejected tool schemas with invalid format.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

packages/tools/createBlogPost/package.json

@@ -104,5 +104,8 @@
         "Format an article with SEO metadata"
       ]
     }
+  },
+  "dependencies": {
+    "zod": "^4.1.13"
   }
 }