feat: add server-side validation for web-based INI deployments

tests/test_ini_validation.py

@@ -0,0 +1,41 @@
+import pytest
+from decnet.ini_loader import load_ini_from_string, validate_ini_string
+
+def test_validate_ini_string_too_large():
+    content = "[" + "a" * (512 * 1024 + 1) + "]"
+    with pytest.raises(ValueError, match="too large"):
+        validate_ini_string(content)
+
+def test_validate_ini_string_empty():
+    with pytest.raises(ValueError, match="is empty"):
+        validate_ini_string("")
+    with pytest.raises(ValueError, match="is empty"):
+        validate_ini_string("   ")
+
+def test_validate_ini_string_no_sections():
+    with pytest.raises(ValueError, match="no sections found"):
+        validate_ini_string("key=value")
+
+def test_load_ini_from_string_amount_limit():
+    content = """
+[general]
+net=192.168.1.0/24
+
+[decky-01]
+amount=101
+archetype=linux-server
+"""
+    with pytest.raises(ValueError, match="exceeds maximum allowed"):
+        load_ini_from_string(content)
+
+def test_load_ini_from_string_valid():
+    content = """
+[general]
+net=192.168.1.0/24
+
+[decky-01]
+amount=5
+archetype=linux-server
+"""
+    cfg = load_ini_from_string(content)
+    assert len(cfg.deckies) == 5