remove Tier-0 dead code: dashboard_layout package and service/models stub

backend/apps/dashboard_layout/ was never mounted in main.py and had no
frontend/electron callers — its SubApp and endpoints were fully superseded
by backend/apps/dashboards/. backend/apps/service/models.py was an empty
placeholder with no importers. Also adds .dead-code-scan/ and the scan
script to .gitignore, and drops the stale dashboard_layout/ entry from
the README directory tree.

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

.gitignore

@@ -54,6 +54,10 @@ backend/coverage_html/
 backend/coverage.xml
 htmlcov/
 
+# Dead-code scan workspace (one-shot scratch — never committed)
+.dead-code-scan/
+backend/scripts/dead_code_scan.py
+
 # Editor noise — per-developer, never useful in repo
 .idea/
 .vscode/

README.md

@@ -160,7 +160,6 @@ backend/
   apps/
     agents/           Agent lifecycle, streaming, worktree management
     dashboards/       Dashboard CRUD and layout persistence
-    dashboard_layout/ Card positions and spatial canvas state
     templates/        Prompt template CRUD
     skills/           Skills CRUD (synced to ~/.claude/skills/)
     tools_lib/        MCP tool configuration and discovery

backend/apps/dashboard_layout/dashboard_layout.py

@@ -1,58 +0,0 @@
-import json
-import os
-import logging
-from contextlib import asynccontextmanager
-from backend.config.Apps import SubApp
-from backend.apps.dashboard_layout.models import DashboardLayout, DashboardLayoutUpdate
-
-logger = logging.getLogger(__name__)
-
-from backend.config.paths import DASHBOARD_LAYOUT_DIR as DATA_DIR
-
-LAYOUT_FILE = os.path.join(DATA_DIR, "layout.json")
-
-
-@asynccontextmanager
-async def dashboard_layout_lifespan():
-    os.makedirs(DATA_DIR, exist_ok=True)
-    yield
-
-
-dashboard_layout = SubApp("dashboard_layout", dashboard_layout_lifespan)
-
-
-def _default_layout() -> DashboardLayout:
-    return DashboardLayout(cards={})
-
-
-def _load() -> DashboardLayout:
-    if not os.path.exists(LAYOUT_FILE):
-        return _default_layout()
-    try:
-        with open(LAYOUT_FILE) as f:
-            data = json.load(f)
-        if "columns" in data and "cards" not in data:
-            logger.info("Detected old column-based layout format, resetting to empty canvas")
-            return _default_layout()
-        return DashboardLayout(**data)
-    except Exception:
-        logger.exception("Failed to load dashboard layout, returning default")
-        return _default_layout()
-
-
-def _save(layout: DashboardLayout):
-    with open(LAYOUT_FILE, "w") as f:
-        json.dump(layout.model_dump(), f, indent=2)
-
-
-@dashboard_layout.router.get("")
-async def get_layout():
-    layout = _load()
-    return layout.model_dump()
-
-
-@dashboard_layout.router.put("")
-async def update_layout(body: DashboardLayoutUpdate):
-    layout = DashboardLayout(cards=body.cards, view_cards=body.view_cards)
-    _save(layout)
-    return layout.model_dump()

backend/apps/dashboard_layout/models.py

@@ -1,27 +0,0 @@
-from pydantic import BaseModel, Field
-
-
-class CardPosition(BaseModel):
-    session_id: str
-    x: float = 0
-    y: float = 0
-    width: float = 420
-    height: float = 280
-
-
-class ViewCardPosition(BaseModel):
-    output_id: str
-    x: float = 0
-    y: float = 0
-    width: float = 480
-    height: float = 360
-
-
-class DashboardLayout(BaseModel):
-    cards: dict[str, CardPosition] = Field(default_factory=dict)
-    view_cards: dict[str, ViewCardPosition] = Field(default_factory=dict)
-
-
-class DashboardLayoutUpdate(BaseModel):
-    cards: dict[str, CardPosition]
-    view_cards: dict[str, ViewCardPosition] = Field(default_factory=dict)

backend/apps/service/models.py

@@ -1,5 +0,0 @@
-"""(Reserved for future use; intentionally empty.)
-
-The service-sync layer ships opaque payload dicts through `submit()` —
-no Pydantic shape exposed in the public repo.
-"""