docs: salvage focused stale PR contributions

- add Vite and Redis pattern skills from closed stale PRs

- add frontend-slides support assets

- port skill-comply runner fixes and LLM prompt/provider regressions

- harden agent frontmatter validation and sync catalog counts

tests/test_builder.py

@@ -24,22 +24,37 @@ class TestPromptBuilder:
         assert len(result) == 2
         assert result[0].role == Role.SYSTEM
 
-    def test_build_adds_system_from_config(self):
-        messages = [Message(role=Role.USER, content="Hello")]
-        builder = PromptBuilder(system_template="You are a pirate.")
-        result = builder.build(messages)
-
-        assert len(result) == 2
-        assert "pirate" in result[0].content
-
-    def test_build_adds_system_from_config(self):
-        messages = [Message(role=Role.USER, content="Hello")]
-        builder = PromptBuilder(config=PromptConfig(system_template="You are a pirate."))
-        result = builder.build(messages)
-
-        assert len(result) == 2
-        assert "pirate" in result[0].content
-    def test_build_with_tools(self):
+    def test_build_adds_system_from_keyword_options(self):
+        messages = [Message(role=Role.USER, content="Hello")]
+        builder = PromptBuilder(system_template="You are a pirate.")
+        result = builder.build(messages)
+
+        assert len(result) == 2
+        assert "pirate" in result[0].content
+
+    def test_build_adds_system_from_prompt_config(self):
+        messages = [Message(role=Role.USER, content="Hello")]
+        builder = PromptBuilder(config=PromptConfig(system_template="You are a pirate."))
+        result = builder.build(messages)
+
+        assert len(result) == 2
+        assert "pirate" in result[0].content
+
+    def test_rejects_config_with_keyword_options(self):
+        with pytest.raises(ValueError, match="Pass either config or PromptBuilder keyword options"):
+            PromptBuilder(
+                config=PromptConfig(system_template="Configured."),
+                system_template="Keyword override.",
+            )
+
+    def test_empty_system_template_does_not_add_blank_system_message(self):
+        messages = [Message(role=Role.USER, content="Hello")]
+        builder = PromptBuilder(system_template="")
+        result = builder.build(messages)
+
+        assert result == messages
+
+    def test_build_with_tools(self):
         messages = [Message(role=Role.USER, content="Search for something")]
         tools = [
             ToolDefinition(name="search", description="Search the web", parameters={}),