Add shared notes with tabbed pages editable by user and AI

Adds a note_pages table backing a tabbed notes panel where the user and
the model can both read and write. Only page titles (plus a short
preview) are injected into the system prompt on every turn; full page
content is kept out of context and fetched on demand via a read_note
tool, with write_note letting the model append to, replace, or create a
page.

Generalizes llm.resolve_web_search into resolve_tool_calls so the
tool-calling loop handles web_search and the new note tools through one
path. The chat stream emits a notes_updated SSE event when the model
edits a note so the frontend panel can refresh; local edits are tracked
as dirty and never clobbered by that refresh.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

backend/app/core/llm.py

@@ -2,13 +2,17 @@ import json
 import logging
 import time
 import traceback
-from typing import AsyncIterator, AsyncGenerator
+from typing import TYPE_CHECKING, AsyncIterator, AsyncGenerator
 from contextlib import asynccontextmanager
 
 import litellm
 from app.core.config import DEFAULT_MODEL, DEBUG
+from app.core.notes import NOTE_TOOLS, execute_note_tool
 from app.core.search.websearch import WEB_SEARCH_TOOL, search_web
 
+if TYPE_CHECKING:
+    from sqlalchemy.orm import Session as DBSession
+
 litellm.drop_params = True
 if DEBUG:
     litellm._turn_on_debug()
@@ -103,32 +107,38 @@ async def embed(texts: list[str], model: str) -> list[list[float]]:
     return [item["embedding"] for item in response.data]
 
 
-async def resolve_web_search(
+async def resolve_tool_calls(
     messages: list[dict],
     model: str | None = None,
     session_id: str | None = None,
+    db: "DBSession | None" = None,
     max_rounds: int = 2,
-) -> tuple[list[dict], list[dict]]:
-    """必要に応じてLLMにweb_searchツールを呼ばせ、検索結果を会話に組み込んだ上でメッセージ列を返す。
+) -> tuple[list[dict], list[dict], bool]:
+    """必要に応じてLLMにツールを呼ばせ、その結果を会話に組み込んだ上でメッセージ列を返す。
 
-    モデルがtool callingに対応していない場合は何もせず元のmessagesをそのまま返す。
-    戻り値: (拡張後のmessages, 実際に検索したクエリと結果のリスト)
+    扱うツールは web_search と共有ノート（read_note / write_note）。ノート系は db が
+    渡されたときだけ提示する。モデルがtool callingに対応していない場合は何もせず
+    元のmessagesをそのまま返す。
+    戻り値: (拡張後のmessages, 実際に検索したクエリと結果のリスト, ノートを変更したか)
     """
     used_model = model or DEFAULT_MODEL
     working_messages = list(messages)
     searches: list[dict] = []
+    notes_changed = False
+
+    tools = [WEB_SEARCH_TOOL] + (NOTE_TOOLS if db is not None else [])
 
     for _ in range(max_rounds):
         try:
             response = await litellm.acompletion(
                 model=used_model,
                 messages=working_messages,
-                tools=[WEB_SEARCH_TOOL],
+                tools=tools,
                 tool_choice="auto",
             )
         except Exception:
-            logger.info("Model %s does not support tool calling; skipping web search", used_model)
-            return messages, searches
+            logger.info("Model %s does not support tool calling; skipping tools", used_model)
+            return messages, searches, notes_changed
 
         choice_message = response.choices[0].message
         tool_calls = getattr(choice_message, "tool_calls", None)
@@ -153,13 +163,19 @@ async def resolve_web_search(
                 args = json.loads(tc.function.arguments or "{}")
             except json.JSONDecodeError:
                 args = {}
-            query = args.get("query", "")
-            results = await search_web(query)
-            if results:
-                tool_text = "\n\n".join(f"[{r['title']}]({r['url']})\n{r['content']}" for r in results)
-                searches.append({"query": query, "results": results})
+
+            name = tc.function.name
+            if name in ("read_note", "write_note") and db is not None:
+                tool_text, changed = execute_note_tool(db, name, args)
+                notes_changed = notes_changed or changed
             else:
-                tool_text = "検索結果が見つかりませんでした。"
+                query = args.get("query", "")
+                results = await search_web(query)
+                if results:
+                    tool_text = "\n\n".join(f"[{r['title']}]({r['url']})\n{r['content']}" for r in results)
+                    searches.append({"query": query, "results": results})
+                else:
+                    tool_text = "検索結果が見つかりませんでした。"
 
             working_messages.append({
                 "role": "tool",
@@ -167,4 +183,4 @@ async def resolve_web_search(
                 "content": tool_text,
             })
 
-    return working_messages, searches
+    return working_messages, searches, notes_changed