Feat v0.5.3 chat polish + integration testing

Conversation search (db.query search_like, chat-core /search endpoint,
sidebar search UI), message pagination polish (scroll preservation,
loading spinner), workflow-chat integration package, and multi-user
E2E test infrastructure.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/workflow-chat/script.star

@@ -0,0 +1,88 @@
+# Workflow Chat — Starlark Backend (v0.1.0)
+#
+# Library package that creates scoped chat conversations when
+# workflow stages require team collaboration.
+#
+# Usage: wire into stage_config as an on_advance hook:
+#   {"on_advance": {"package_id": "workflow-chat", "entry_point": "on_advance"}}
+#
+# Expected stage_data keys:
+#   title              — conversation title (optional, defaults to "Workflow Discussion")
+#   team_members       — list of {id, display_name} dicts
+#   creator_id         — user ID of the workflow initiator
+#   creator_display_name — display name of the workflow initiator
+#
+# Modules: db, json, realtime (via chat-core dependency)
+
+chat = lib.require("chat-core")
+
+
+def _str(v):
+    if v == None:
+        return ""
+    return str(v)
+
+
+def on_advance(ctx):
+    """Hook called when a workflow advances to a team-audience stage.
+
+    Creates a group conversation with all team members and sends
+    a system message linking back to the workflow instance.
+
+    Args:
+        ctx: dict with {instance_id, previous_stage, current_stage, stage_data}
+
+    Returns:
+        dict with {stage_data} containing enriched data with conversation_id,
+        or None if no team members are present.
+    """
+    data = ctx.get("stage_data", {})
+    if type(data) == "string":
+        data = json.decode(data) if data else {}
+
+    instance_id = _str(ctx.get("instance_id", ""))
+    members = data.get("team_members", [])
+    creator_id = _str(data.get("creator_id", ""))
+    creator_name = _str(data.get("creator_display_name", ""))
+    title = _str(data.get("title", "")) or "Workflow Discussion"
+
+    # Skip if no team members to add
+    if not members:
+        return None
+
+    # Check if conversation already exists for this instance (idempotency)
+    existing_cid = _str(data.get("conversation_id", ""))
+    if existing_cid:
+        return None
+
+    # Build participants list
+    participants = []
+    for m in members:
+        mid = _str(m.get("id", ""))
+        if mid and mid != creator_id:
+            participants.append({
+                "id": mid,
+                "display_name": _str(m.get("display_name", "")),
+            })
+
+    # Create conversation scoped to this workflow instance
+    conv = chat.create(
+        title=title + " [" + instance_id[:8] + "]",
+        type="group",
+        participants=participants,
+        creator_id=creator_id,
+        creator_display_name=creator_name,
+    )
+
+    cid = _str(conv.get("id", ""))
+
+    # Send system message linking to the workflow
+    chat.send(cid, creator_id, "Conversation created for workflow instance " + instance_id, "system")
+
+    # Return enriched stage_data with conversation_id
+    enriched = {}
+    for k in data:
+        enriched[k] = data[k]
+    enriched["conversation_id"] = cid
+
+    return {"stage_data": enriched}