M3 graph view: /api/graph + force-directed SVG

- graph blueprint: GET /api/graph resolves note_links to target notes by
  normalized title (owner-scoped, non-trashed, self-excluded) → {nodes, edges}
  of connected notes.
- GraphView: hand-rolled force simulation (repulsion + edge springs + centering,
  cooling over ~400 frames), SVG nodes/edges, click a node to open it (reuses the
  editor with link navigation). Sidebar Graph entry + route; empty state.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FRgehjoz7Yv8LkUfADxACm

src/thoughtsync/app.py

@@ -10,6 +10,7 @@ from . import __version__
 from .auth import bp as auth_bp
 from .config import Config
 from .db import session_scope
+from .graph import bp as graph_bp
 from .labels import bp as labels_bp
 from .notes import bp as notes_bp
 from .settings import get_public_config, get_setting, load_or_create_secret_key
@@ -33,6 +34,7 @@ def create_app() -> Quart:
     app.register_blueprint(auth_bp)
     app.register_blueprint(notes_bp)
     app.register_blueprint(labels_bp)
+    app.register_blueprint(graph_bp)
     app.register_blueprint(settings_bp)
 
     @app.before_serving

src/thoughtsync/graph.py

@@ -0,0 +1,52 @@
+from __future__ import annotations
+
+from quart import Blueprint, g, jsonify
+from sqlalchemy import func, select
+from sqlalchemy.orm import aliased
+
+from .auth import login_required
+from .db import session_scope
+from .models.note import Note
+from .models.note_link import NoteLink
+
+bp = Blueprint("graph", __name__, url_prefix="/api/graph")
+
+
+@bp.get("")
+@login_required
+async def get_graph():
+    """Wiki-link graph: nodes are the owner's connected notes, edges are resolved
+    [[links]] (note_links.target_norm matched to a note's normalized title)."""
+    source = aliased(Note)
+    target = aliased(Note)
+    stmt = (
+        select(source.id, target.id)
+        .select_from(NoteLink)
+        .join(source, source.id == NoteLink.source_id)
+        .join(target, func.lower(func.trim(target.title)) == NoteLink.target_norm)
+        .where(
+            source.owner_id == g.user_id,
+            source.deleted_at.is_(None),
+            target.owner_id == g.user_id,
+            target.deleted_at.is_(None),
+            source.id != target.id,
+        )
+    )
+    async with session_scope() as db:
+        rows = (await db.execute(stmt)).all()
+        edges = []
+        node_ids: set = set()
+        seen: set = set()
+        for src_id, tgt_id in rows:
+            key = (src_id, tgt_id)
+            if key in seen:
+                continue
+            seen.add(key)
+            edges.append({"source": str(src_id), "target": str(tgt_id)})
+            node_ids.add(src_id)
+            node_ids.add(tgt_id)
+        nodes = []
+        if node_ids:
+            note_rows = (await db.scalars(select(Note).where(Note.id.in_(node_ids)))).all()
+            nodes = [{"id": str(n.id), "title": n.title or "Untitled"} for n in note_rows]
+        return jsonify({"nodes": nodes, "edges": edges})