Clean up LSP diagnostics across backend and frontend

Backend (nvcurve/):
- hal/fans.py, hal/limits.py, hal/gpu.py: replace conditional pynvml
  imports with the established 'pynvml: Any = _pynvml_import' pattern
  (fixes ~50 'possibly unbound' errors); type the result dicts; guard
  query_interface() results; explicit uuid/pci-bus parsing (int, hex
  convention documented); modernize Optional[T] -> T | None
- cli.py: fix 'curve_state' possibly-unbound and snap_path None handling
  in cmd_setup; wrap unchecked int()/open()/makedirs() calls in
  try/except with clean CLI errors; add module logger for silent
  except-pass blocks; raise ... from exc; fix unused loop vars and
  set-comprehension
- hal/snapshot.py: filepath: str | None; wrap all file ops; sorted
  imports; remove unused CT_POINTS import
- daemon.py: extract 0o666 to _SOCKET_MODE constant (intentional for
  /run sockets) with nosemgrep
- server.py: nosemgrep for Python 3.7-compat false positive (project
  requires >= 3.12); log previously-swallowed exception
- profiles/native.py, profiles/apply.py: wrap file ops and int(k)
  profile-key parsing; sorted imports; modernize typing

Frontend (frontend/src):
- Add .js extensions to all relative imports (standard TS-ESM; Vite
  resolves .js -> .ts)
- React.FormEvent (deprecated in React 19 types) -> React.SubmitEvent
- catch (e: any) -> catch (e: unknown) + instanceof Error narrowing
- React-hooks: move ref writes from render into effects; convert
  viewport reset to render-phase state adjustment; split
  selectPoint(index, multi) into selectPoint + togglePoint (no flag
  argument); remove non-null assertion
- Static inline styles -> Tailwind classes (dynamic positioning/cursor
  styles kept)
- Remove non-standard 'container' option from scrollIntoView (browsers
  ignore unknown options) which had orphaned a @ts-expect-error
- Object.fromEntries for Map -> Record conversion

Tooling:
- .gitignore: ignore .codegraph/ local tool data

Verified: tsc --noEmit, vite production build, python imports, and
full LSP scan (0 errors/warnings in both projects).

frontend/src/App.tsx

@@ -1,24 +1,24 @@
-import { useGpu } from "./hooks/useGpu";
-import { useCurve } from "./hooks/useCurve";
-import { useMonitor } from "./hooks/useMonitor";
-import { useDashboard } from "./hooks/useDashboard";
-import { StatusBar } from "./components/Monitor/StatusBar";
-import { LiveMonitor } from "./components/Monitor/LiveMonitor";
-import { Dashboard } from "./components/Dashboard/Dashboard";
-import { CurveEditor } from "./components/CurveEditor/CurveEditor";
-import { PointTable } from "./components/PointTable/PointTable";
-import { PerformancePanel } from "./components/Limits/PerformancePanel";
-import { PerformanceMonitor } from "./components/Monitor/PerformanceMonitor";
-import { FanMonitor } from "./components/Monitor/FanMonitor";
-import { FanCurveEditor } from "./components/Fans/FanCurveEditor";
-import { ProfilePanel } from "./components/Profiles/ProfilePanel";
-import { api, onUnauthorized } from "./api/client";
-import { LoginScreen } from "./components/Auth/LoginScreen";
-import { useCurveStore } from "./store/curveStore";
+import { useGpu } from "./hooks/useGpu.js";
+import { useCurve } from "./hooks/useCurve.js";
+import { useMonitor } from "./hooks/useMonitor.js";
+import { useDashboard } from "./hooks/useDashboard.js";
+import { StatusBar } from "./components/Monitor/StatusBar.js";
+import { LiveMonitor } from "./components/Monitor/LiveMonitor.js";
+import { Dashboard } from "./components/Dashboard/Dashboard.js";
+import { CurveEditor } from "./components/CurveEditor/CurveEditor.js";
+import { PointTable } from "./components/PointTable/PointTable.js";
+import { PerformancePanel } from "./components/Limits/PerformancePanel.js";
+import { PerformanceMonitor } from "./components/Monitor/PerformanceMonitor.js";
+import { FanMonitor } from "./components/Monitor/FanMonitor.js";
+import { FanCurveEditor } from "./components/Fans/FanCurveEditor.js";
+import { ProfilePanel } from "./components/Profiles/ProfilePanel.js";
+import { api, onUnauthorized } from "./api/client.js";
+import { LoginScreen } from "./components/Auth/LoginScreen.js";
+import { useCurveStore } from "./store/curveStore.js";
 import { Toaster } from "sonner";
 import { Loader, ChevronDown } from "lucide-react";
 import { useState, useRef, useEffect } from "react";
-import type { FanState } from "./types";
+import type { FanState } from "./types.js";
 
 type AuthState = "checking" | "login" | "ok";