feat(chat): multi-turn Chat Session with Conversation history sidebar

Grounded Ask owns the product chat UI: persistent thread_id across a
Chat Session, New chat / Continue conversation, and a sidebar that lists
Conversations from the Conversation Record with formatted run metadata
(timing, tokens, evidence chunks).

Co-authored-by: Cursor <cursoragent@cursor.com>

pyproject.toml

@@ -0,0 +1,24 @@
+[project]
+name = "tamasino-ai-grounded-ask"
+version = "0.1.0"
+description = "Grounded Ask: upload tenant docs, ask once, read the answer with Sources"
+readme = "README.md"
+requires-python = ">=3.11"
+dependencies = [
+    "httpx>=0.28.1",
+    "python-dotenv>=1.1.0",
+    "streamlit>=1.45.0",
+]
+
+[dependency-groups]
+dev = [
+    "ruff>=0.11.0",
+]
+
+[tool.ruff]
+line-length = 100
+target-version = "py311"
+
+[tool.ruff.lint]
+select = ["E", "F", "I", "UP", "B"]
+ignore = ["E402"]