Consolidate Odysseus agent harness and tool contracts

tests/test_tool_phase_ttft_static.py

@@ -0,0 +1,13 @@
+from pathlib import Path
+
+
+CHAT_JS = Path(__file__).parents[1] / "static" / "js" / "chat.js"
+
+
+def test_tool_start_stops_initial_ttft_before_tool_execution():
+    source = CHAT_JS.read_text()
+    branch = source.index("} else if (json.type === 'tool_start') {")
+    mark_output = source.index("markFirstVisibleOutput();", branch)
+    close_thinking = source.index("_closeOpenThinkingMarkup(_isBg);", branch)
+
+    assert branch < mark_output < close_thinking