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).

.github/workflows/release.yml

@@ -238,6 +238,7 @@ jobs:
             SNAPOTTER_ANALYTICS=on
             SNAPOTTER_POSTHOG_PROJECT_ID=${{ secrets.SNAPOTTER_POSTHOG_KEY }}
             SNAPOTTER_SENTRY_DSN=${{ secrets.SNAPOTTER_SENTRY_DSN }}
+            SNAPOTTER_SENTRY_DSN_WEB=${{ secrets.SNAPOTTER_SENTRY_DSN_WEB }}
             SENTRY_RELEASE=${{ needs.release.outputs.new_version }}
           secrets: |
             sentry_auth_token=${{ secrets.SENTRY_AUTH_TOKEN }}