debug: add console logging for MCP tool calls
Add detailed logging at each level of MCP tool call chain:
- chat.svelte.ts: executeToolCalls logs tool calls being processed
- mcp.svelte.ts: callTool logs before/after service calls
- mcp.ts: McpService.callTool logs timing and responses
This helps debug issues where tool calls appear stuck.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
