fix: error-only Sentry telemetry, storm-proof capture, and crash fixes (#476)

Removes Sentry tracing entirely (BullMQ idle polling burned 4.8M transactions in 2 days at the baked 0.1 rate), decouples PostHog sampling, and replaces the type-only error scrub with a vetted-field sanitizer plus SafeError/ToolInputError contracts. One classified capture path with per-signature throttles and a per-process ceiling makes storms impossible (NODE-1E was 4,541 events from one 30s loop). Browser errors move to a dedicated web Sentry project with their own source maps. Adds the SNAPOTTER_TELEMETRY runtime kill switch and silences test fleets.

Crash fixes: remote 204/304 SSRF process kill (NODE-20), conversion-preset boot crash loop (NODE-21), Redis version preflight + unhandled subscribe rejection (NODE-1T), Sign PDF on plain-http origins (NODE-1K/1M), wavesurfer/pdf.js teardown rejections (NODE-1P/1N), bundle-import ZlibError to 400 (NODE-1Z), chart-maker input errors declassified (NODE-1H/1J), asset requests skip the session DB lookup (NODE-1D).

apps/web/src/components/tools/sign-canvas.tsx

@@ -5,6 +5,7 @@ import { forwardRef, useEffect, useImperativeHandle, useRef, useState } from "re
 import { useTranslation } from "@/contexts/i18n-context";
 import { toNormalizedRect } from "@/lib/sign-geometry";
 import type { SavedSignature } from "@/lib/signature-store";
+import { safeRandomUUID } from "@/lib/uuid";
 
 pdfjs.GlobalWorkerOptions.workerSrc = new URL(
   "pdfjs-dist/build/pdf.worker.min.mjs",
@@ -90,7 +91,11 @@ export const SignCanvas = forwardRef<SignCanvasRef, Props>(function SignCanvas(
       setPageCount(doc.numPages);
       setPage(0);
       setDocReady(true);
-    })();
+    })().catch(() => {
+      // loadingTask.destroy() in the cleanup rejects the in-flight promise;
+      // swallowing it is the fix for Sentry NODE-1N. A genuine load failure
+      // leaves docReady false, which the existing UI already handles.
+    });
     return () => {
       cancelled = true;
       docRef.current?.loadingTask.destroy();
@@ -181,7 +186,10 @@ export const SignCanvas = forwardRef<SignCanvasRef, Props>(function SignCanvas(
       }
       layer.batchDraw();
       onSelectionChange?.(false);
-    })();
+    })().catch(() => {
+      // getPage()/render() reject when the loadingTask is destroyed mid-render
+      // (file swap or unmount); expected teardown, same as the load effect.
+    });
     return () => {
       cancelled = true;
     };
@@ -241,7 +249,7 @@ export const SignCanvas = forwardRef<SignCanvasRef, Props>(function SignCanvas(
           layer.add(node);
           tr.nodes([node]);
           layer.batchDraw();
-          placementsRef.current.push({ id: crypto.randomUUID(), page, node });
+          placementsRef.current.push({ id: safeRandomUUID(), page, node });
           onSelectionChange?.(true);
           emitCount();
         };

apps/web/src/components/tools/sign-pdf-settings.tsx

@@ -10,6 +10,7 @@ import {
   type SavedSignature,
 } from "@/lib/signature-store";
 import { generateId } from "@/lib/utils";
+import { safeRandomUUID } from "@/lib/uuid";
 import { useFileStore } from "@/stores/file-store";
 import type { SignCanvasRef } from "./sign-canvas";
 import { SignaturePad } from "./signature-pad";
@@ -126,7 +127,7 @@ export function SignPdfSettings({ signProps }: { signProps?: SignProps }) {
   const handleSavePad = (dataUrl: string, remember: boolean) => {
     const sig: SavedSignature = remember
       ? addSignature(dataUrl)
-      : { id: crypto.randomUUID(), dataUrl, createdAt: Date.now() };
+      : { id: safeRandomUUID(), dataUrl, createdAt: Date.now() };
     if (remember) refresh();
     signProps?.canvasRef.current?.addSignature(sig);
     setPadOpen(false);