feat: add emulated tool-calling bridge for Lingma

Add a proxy-side tool emulation layer so Lingma requests can surface stable OpenAI tool_calls and Anthropic tool_use blocks even when upstream tool events are missing or inconsistent.

Constraint: Keep native Lingma tool event bridging as the first path and layer emulation as a fallback

Rejected: Depend exclusively on Lingma native tool/invoke events | tool visibility remains inconsistent across models and transports

Confidence: high

Scope-risk: moderate

scripts/smoke_tool_calls.sh

@@ -0,0 +1,117 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+ROOT_DIR="$(cd "$(dirname "$0")/.." && pwd)"
+ENV_FILE="$ROOT_DIR/.env"
+
+if [[ ! -f "$ENV_FILE" ]]; then
+  printf 'missing .env: %s\n' "$ENV_FILE" >&2
+  exit 1
+fi
+
+PORT="$(python3 - <<'PY'
+from pathlib import Path
+env = Path("/root/lingma-openai-gateway/.env")
+vals = {}
+for line in env.read_text().splitlines():
+    line = line.strip()
+    if not line or line.startswith('#') or '=' not in line:
+        continue
+    k, v = line.split('=', 1)
+    vals[k.strip()] = v.strip()
+print(vals.get('PORT', '13013'))
+PY
+)"
+
+API_KEY="$(python3 - <<'PY'
+from pathlib import Path
+env = Path("/root/lingma-openai-gateway/.env")
+vals = {}
+for line in env.read_text().splitlines():
+    line = line.strip()
+    if not line or line.startswith('#') or '=' not in line:
+        continue
+    k, v = line.split('=', 1)
+    vals[k.strip()] = v.strip()
+keys = vals.get('API_KEYS', '')
+print(keys.split(',')[0].strip())
+PY
+)"
+
+BASE_URL="http://127.0.0.1:${PORT}"
+
+printf '\n[1/5] /v1/models\n'
+curl -fsS "$BASE_URL/v1/models" \
+  -H "Authorization: Bearer ${API_KEY}" | python3 -m json.tool
+
+printf '\n[2/5] OpenAI non-stream tool call\n'
+curl -fsS "$BASE_URL/v1/chat/completions" \
+  -H "Authorization: Bearer ${API_KEY}" \
+  -H 'Content-Type: application/json' \
+  -d '{
+    "model": "org_auto",
+    "stream": false,
+    "messages": [
+      {"role": "system", "content": "Use tools when available."},
+      {"role": "user", "content": "Use fetch_weather for Hangzhou and return the tool call."}
+    ],
+    "tools": [
+      {"type": "function", "function": {"name": "fetch_weather", "description": "Get weather for a city", "parameters": {"type": "object", "properties": {"city": {"type": "string"}}, "required": ["city"]}}}
+    ],
+    "tool_choice": {"type": "function", "function": {"name": "fetch_weather"}}
+  }' | python3 -m json.tool
+
+printf '\n[3/5] Anthropic non-stream tool use\n'
+curl -fsS "$BASE_URL/v1/messages" \
+  -H "x-api-key: ${API_KEY}" \
+  -H 'anthropic-version: 2023-06-01' \
+  -H 'Content-Type: application/json' \
+  -d '{
+    "model": "claude-3-5-sonnet-20241022",
+    "max_tokens": 256,
+    "stream": false,
+    "messages": [
+      {"role": "user", "content": "Use fetch_weather for Hangzhou and return the tool call."}
+    ],
+    "tools": [
+      {"name": "fetch_weather", "description": "Get weather for a city", "input_schema": {"type": "object", "properties": {"city": {"type": "string"}}, "required": ["city"]}}
+    ],
+    "tool_choice": {"type": "tool", "name": "fetch_weather"}
+  }' | python3 -m json.tool
+
+printf '\n[4/5] OpenAI stream tool call\n'
+curl -fsS -N "$BASE_URL/v1/chat/completions" \
+  -H "Authorization: Bearer ${API_KEY}" \
+  -H 'Content-Type: application/json' \
+  -d '{
+    "model": "org_auto",
+    "stream": true,
+    "messages": [
+      {"role": "system", "content": "Use tools when available."},
+      {"role": "user", "content": "Use fetch_weather for Hangzhou and return the tool call."}
+    ],
+    "tools": [
+      {"type": "function", "function": {"name": "fetch_weather", "description": "Get weather for a city", "parameters": {"type": "object", "properties": {"city": {"type": "string"}}, "required": ["city"]}}}
+    ],
+    "tool_choice": {"type": "function", "function": {"name": "fetch_weather"}}
+  }'
+
+printf '\n[5/5] Anthropic stream tool use\n'
+curl -fsS -N "$BASE_URL/v1/messages" \
+  -H "x-api-key: ${API_KEY}" \
+  -H 'anthropic-version: 2023-06-01' \
+  -H 'Content-Type: application/json' \
+  -d '{
+    "model": "claude-3-5-sonnet-20241022",
+    "max_tokens": 256,
+    "stream": true,
+    "messages": [
+      {"role": "user", "content": "Use fetch_weather for Hangzhou and return the tool call."}
+    ],
+    "tools": [
+      {"name": "fetch_weather", "description": "Get weather for a city", "input_schema": {"type": "object", "properties": {"city": {"type": "string"}}, "required": ["city"]}}
+    ],
+    "tool_choice": {"type": "tool", "name": "fetch_weather"}
+  }'
+
+printf '\nsmoke tool-call checks completed\n'