chore: remove Sentry

[guanbinrui]

Summary

Removes Sentry error/performance monitoring entirely, keeping Mixpanel analytics fully intact.

• Deletes packages/sentry (the @sentry/browser bundle injected as a content script/service-worker script) and its build task (packages/scripts/src/projects/sentry.ts).
• Deletes the Sentry telemetry provider (web3-telemetry/src/providers/Sentry.ts) and the Sentry-only fetch-transaction tracer (captureFetchTransaction.ts); TelemetryAPI.captureException becomes a no-op since Sentry was its only backing provider (3 call sites left as-is, now harmlessly calling a no-op).
• Bug fix found along the way: MixpanelAPI.captureEvent was incorrectly gated on the sentry_enabled/sentry_event_enabled flags instead of its own dedicated mixpanel_enabled/mixpanel_event_enabled flags (both default to the same isProd value today, so this is not a behavior change — just removes an accidental coupling to Sentry's flags that would otherwise have broken Mixpanel once those flags were deleted).
• Removes all 7 sentry_* feature flags, the MASK_SENTRY/MASK_SENTRY_DSN env vars and their webpack DefinePlugin injection, the sentry.js/sentry-patch.js content-script injection (both the dynamic contentScriptList and the MV3 service worker's importScripts), the @sentry/browser no-restricted-imports eslint rule, and the CI "Create Sentry release" step (including its now-unnecessary git-worktreeconfig workaround) and MASK_SENTRY* secrets from compile.yml.

Test plan

• tsc -b --force clean (0 errors) across the whole monorepo.
• eslint clean on all touched files.
• knip clean — no orphaned files/exports left behind.
• Repo-wide grep sweep for sentry/@sentry/MASK_SENTRY*/SENTRY_* returns zero real hits (only unrelated phishing-domain blacklist entries that coincidentally contain "sentry" as a substring).
• Full production build (pnpm run build) — verifying now, will confirm build output contains no sentry.js/sentry-patch.js.
• Manual browser QA (not done here): load the built extension and confirm no console errors from the removed Sentry init, and that Mixpanel event tracking still fires normally.

Co-Authored-By: Claude Sonnet 5 noreply@anthropic.com

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https://claude.ai/code/session_01Ly4aKgVW1wnPu2LfzTQuJi