feat(component-sdk): add tool mode metadata for agent-callable components

[betterclever]

Summary

Adds tool mode metadata for agent-callable components, allowing components to be exposed as MCP tools.

Changes

✨ Features

• Add `agentTool` configuration to component UI metadata
• Add `ToolMetadata` and `ToolInputSchema` types for MCP compatibility
• Add helper functions:
  • `isAgentCallable()` - check if a component is configured as an agent-callable tool
  • `inferBindingType()` - infer credential vs action input binding
  • `getCredentialInputIds()` / `getActionInputIds()` - filter inputs by binding type
  • `getToolSchema()` - generate JSON Schema for action inputs only
  • `getToolName()` / `getToolDescription()` - get tool metadata
  • `getToolMetadata()` - get complete MCP-compatible tool metadata

🐛 Bug Fixes

• Fixed P2 bug: `json`/`any` ports were incorrectly forced to `type: 'object'` in MCP tool schemas
  • Now uses Zod's built-in `toJSONSchema()` for accurate type conversion:
    • `z.any()` → `{}` (empty schema = any JSON value) ✅
    • `z.union([...])` → `{ anyOf: [...] }` ✅
    • `z.enum([...])` → `{ type: 'string', enum: [...] }` ✅
    • `z.literal('X')` → `{ type: 'string', const: 'X' }` ✅
    • `z.record(...)` → `{ type: 'object', additionalProperties: {...} }` ✅

🏗️ Refactoring

• Uses official `@modelcontextprotocol/sdk` types for `Tool` and `ToolInputSchema`
• Simplified `tool-helpers.ts` by removing redundant helper functions
• Reuses existing `getActionInputIds()` function instead of duplicating logic

Testing

All component-sdk tests pass:
```
126 pass
7 skip
0 fail
```

Type Definitions

```typescript
import type { Tool } from '@modelcontextprotocol/sdk/types.js';

// Uses MCP SDK's official Tool.inputSchema type
export type ToolInputSchema = Tool['inputSchema'];

export interface ToolMetadata {
name: string;
description: string;
inputSchema: ToolInputSchema;
}
```

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Do not force json/any ports to object in tool schema

portTypeToJsonSchemaType maps both json and any to the JSON Schema type object, but coercePrimitive in ports.ts accepts any value for these port types (strings, numbers, arrays, etc.). This makes the generated MCP inputSchema reject legitimate non-object inputs (e.g., a JSON array or string) or mislead agents about the expected shape. Consider omitting type for these ports or using a permissive schema so tool calls that pass valid non-object JSON aren’t rejected.

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[betterclever]

Superseded by consolidated PR #243 (branch: mcp-tool-mode) that contains the full MCP tool‑mode stack with updated description.

[betterclever]

Closing in favor of #243 (full MCP tool‑mode stack consolidated).