feat(discovery): detect llama.cpp servers and label local providers (#4729)

* feat(discovery): detect llama.cpp servers and label local providers

Scan port 8080 (llama-server) and 11435 (APFEL) during discovery, fingerprint
llama.cpp via its native /props endpoint, and label well-known local serving
ports (8080 llama.cpp, 8000 vLLM, 1234 LM Studio, 11434 Ollama) consistently
in both the Python provider helper and the JS endpoint UI. Adds a llama.cpp
hint to the /setup slash command.

* fix(discovery): don't infer the serving tool from the port alone

Per review: vLLM, SGLang, llama.cpp and plain OpenAI-compatible servers all
share 8000/8080, so labeling by port mislabels real setups (a vLLM box on 8080
shown as llama.cpp). Drop the port->tool assertions from _provider_label and
providerLabel; the authoritative signal is the /props fingerprint done during
discovery, which is unchanged. Loopback now reads a neutral 'local endpoint' /
'Local'. Tests updated to assert the neutral labels.

tests/test_provider_label_js.py

@@ -0,0 +1,54 @@
+"""providerLabel() in providers.js must NOT name the serving tool from the port,
+mirroring the Python _provider_label() in src/llm_core.py.
+
+A port is not authoritative: vLLM, SGLang, llama.cpp and plain OpenAI-compatible
+servers all routinely share 8000/8080, so a port-only label would mislabel real
+setups (e.g. a vLLM box on :8080 shown as "llama.cpp"). The actual tool is
+identified by probing /props during discovery and stored as the endpoint's name.
+The rule here: loopback → "Local"; private-LAN IPs → "Local"; known remote
+provider hosts → their provider name.
+"""
+import json
+import re
+import shutil
+import subprocess
+from pathlib import Path
+
+import pytest
+
+_REPO = Path(__file__).resolve().parent.parent
+_SRC = _REPO / "static" / "js" / "providers.js"
+_HAS_NODE = shutil.which("node") is not None
+
+
+def _provider_label(url: str) -> str | None:
+    src = _SRC.read_text(encoding="utf-8")
+    # Strip the `export` keyword so the module runs standalone.
+    src_runnable = src.replace("export function providerLabel", "function providerLabel")
+    src_runnable = src_runnable.replace("export default {", "const _default = {")
+    js = src_runnable + f"\nconsole.log(JSON.stringify(providerLabel({json.dumps(url)})));"
+    proc = subprocess.run(
+        ["node", "--input-type=module"],
+        input=js, capture_output=True, text=True, encoding="utf-8",
+        cwd=str(_REPO), timeout=30,
+    )
+    assert proc.returncode == 0, proc.stderr
+    return json.loads(proc.stdout.strip())
+
+
+@pytest.mark.skipif(not _HAS_NODE, reason="node binary not on PATH")
+@pytest.mark.parametrize("url,expected", [
+    # Loopback never names the tool from the port — it isn't authoritative.
+    ("http://localhost:8080/v1",      "Local"),
+    ("http://127.0.0.1:8080/v1",      "Local"),
+    ("http://localhost:8000/v1",      "Local"),
+    ("http://localhost:1234/v1",      "Local"),
+    ("http://localhost:11434/api",    "Local"),
+    ("http://localhost:9999/v1",      "Local"),
+    # Known remote provider hosts are still labeled by host suffix.
+    ("https://api.openai.com/v1",     "OpenAI"),
+    ("https://api.groq.com/openai/v1","Groq"),
+    ("http://192.168.1.50:8080",      "Local"),      # private LAN: no port branding
+])
+def test_provider_label_neutral_for_loopback(url, expected):
+    assert _provider_label(url) == expected