Merge remote-tracking branch 'origin/main' into codex/81234-live-main-final

# Conflicts:
#	tui_gateway/methods_prompt.py
#	tui_gateway/server.py

agent/turn_context.py

@@ -42,6 +42,7 @@ from agent.context_engine import automatic_compaction_status_message
 from agent.iteration_budget import IterationBudget
 from agent.memory_manager import build_memory_context_block
 from agent.memory_provider import is_trivial_prompt
+from agent.message_metadata import append_message, stamp_message_timestamp
 from agent.model_metadata import (
     estimate_messages_tokens_rough,
     estimate_request_tokens_rough,
@@ -493,6 +494,17 @@ def build_turn_context(
     # after primary restoration has settled the runtime.
     try:
         from agent.auxiliary_client import set_runtime_main
+        from agent.prompt_cache_scope import resolve_prompt_cache_scope_safe
+        # Rotation-stable prompt-cache scope. Memoized per segment on the
+        # agent, so this is a DB walk at most once per segment — except a
+        # brand-new session whose row lands later in turn setup
+        # (_ensure_db_session); that first turn falls back to the physical
+        # id here and the first build_api_kwargs re-resolves. Stays valid
+        # through a mid-turn compression rotation because the lineage root
+        # is by definition rotation-invariant (#79017). Resolved with the
+        # never-raising variant OUTSIDE the argument list, so a resolution
+        # failure can only lose the scope — never the whole runtime binding.
+        _cache_scope = resolve_prompt_cache_scope_safe(agent) or ""
         set_runtime_main(
             getattr(agent, "provider", "") or "",
             getattr(agent, "model", "") or "",
@@ -502,6 +514,7 @@ def build_turn_context(
             api_mode=getattr(agent, "api_mode", "") or "",
             auth_mode=getattr(agent, "auth_mode", "") or "",
             session_id=getattr(agent, "session_id", "") or "",
+            cache_scope=_cache_scope,
         )
     except Exception:
         pass
@@ -633,9 +646,15 @@ def build_turn_context(
         # the same dict and any close-path durable marker.
         user_msg["content"] = user_message
     else:
-        user_msg = {"role": "user", "content": user_message}
+        user_msg = stamp_message_timestamp(
+            {"role": "user", "content": user_message},
+            timestamp=persist_user_timestamp,
+        )
         if isinstance(pending_cli_message, dict):
             agent._pending_cli_user_message = None
+    # CLI input is stamped when staged. Gateway input may carry the platform
+    # event time. Preserve either value and cover any legacy unstamped handoff.
+    stamp_message_timestamp(user_msg, timestamp=persist_user_timestamp)
 
     # Hydrate todo store from conversation history.
     if conversation_history and not agent._todo_store.has_items():
@@ -667,7 +686,7 @@ def build_turn_context(
         if persist_user_display_metadata:
             user_msg["display_metadata"] = persist_user_display_metadata
 
-    messages.append(user_msg)
+    append_message(messages, user_msg)
     current_turn_user_idx = len(messages) - 1
     agent._persist_user_message_idx = current_turn_user_idx