refactor(ipuaro): simplify LLM integration with pure XML tool format

Refactor OllamaClient to use pure XML format for tool calls as
designed in CONCEPT.md. Removes dual system (Ollama native tools +
XML parser) in favor of single source of truth (ResponseParser).

Changes:
- Remove tools parameter from ILLMClient.chat() interface
- Remove convertTools(), convertParameters(), extractToolCalls()
- Add XML format instructions to system prompt with examples
- Add CDATA support in ResponseParser for multiline content
- Add tool name validation with helpful error messages
- Move ToolDef/ToolParameter to shared/types/tool-definitions.ts

Benefits:
- Simplified architecture (single source of truth)
- CONCEPT.md compliance (pure XML as designed)
- Better validation (early detection of invalid tools)
- Reduced complexity (fewer format conversions)

Tests: 1444 passed (+4 new tests)
Coverage: 97.83% lines, 91.98% branches, 99.16% functions

packages/ipuaro/tests/unit/application/use-cases/HandleMessage.test.ts

@@ -198,12 +198,12 @@ describe("HandleMessage", () => {
             expect(toolMessages.length).toBeGreaterThan(0)
         })
 
-        it("should return error for unknown tools", async () => {
+        it("should return error for unregistered tools", async () => {
             vi.mocked(mockTools.get).mockReturnValue(undefined)
             vi.mocked(mockLLM.chat)
                 .mockResolvedValueOnce(
                     createMockLLMResponse(
-                        '<tool_call name="unknown_tool"><param>value</param></tool_call>',
+                        '<tool_call name="get_complexity"><path>src</path></tool_call>',
                         true,
                     ),
                 )