#986 Zed says Tools Unsupported: `/props` has no `chat_template_caps`

Description

## What happens

Strata already does tool calls (OpenAI / Anthropic / Responses). Zed still shows **Tools Unsupported**.

Zed's llama.cpp provider (the one that talks to `/v1/models` and `/props`, which Strata already mimics) decides tools from `GET /props` → `chat_template_caps.supports_tools` or `supports_tool_calls`. Strata's `/props` never sends that object, so a loaded model is treated as tools-off.

## Check

```
curl -s http://127.0.0.1:8080/props | python -c "import json,sys; p=json.load(sys.stdin); print('chat_template_caps' in p, p.get('chat_template_caps'))"
```

On current main that prints `False None`. llama.cpp's `/props` includes both `supports_tools` and `supports_tool_calls`.

## Fix

Put `chat_template_caps` on `/props` (tools, parallel calls, system role, preserve reasoning). Zed then offers tools without a settings override.

Note: Zed's generic OpenAI-compatible provider never reads `/props`. That path still needs `"capabilities": {"tools": true, "chat_completions": true}` on the model in Zed's settings. This issue is only the llama.cpp discovery path.