v2.18.4

Chore: remove dead Segment analytics code (#762)

## Summary

The Segment analytics module (`packages/main/src/logging/analytics.ts`)
has been orphaned since the Vue → React migration in #579. The exported
`initAnalyticsEventHandling`, `trackEvent`, and `trackPage` functions
are not called anywhere in the current codebase — verified via
exhaustive grep across `.ts`, `.tsx`, and `.js` files in
`packages/main`, `packages/preload`, and `packages/renderer`.

The previous call site was in `src/ui/components/app/MainContent.vue`,
which was deleted as part of the migration. The React replacement never
re-wired the analytics call.

This PR removes the dead module and its supporting infrastructure:

- Deletes `packages/main/src/logging/analytics.ts` (70 lines)
- Removes `analytics-node`, `@types/analytics-node`, and
`node-machine-id` from `package.json`
- Removes `VITE_SEGMENT_WRITE_KEY` from the env type definition and the
release workflow

Sentry remains in place — it is still wired up for the user-initiated
"Report a problem" flow.

## Follow-ups (out of scope for this PR)

- The `SEGMENT_WRITE_KEY` GitHub Actions secret can now be deleted from
repository settings.
- The corresponding Segment source can be archived.

## Test plan

- [x] `yarn typecheck` passes
- [x] `yarn build` passes
- [x] `yarn test:main`, `yarn test:preload`, `yarn test:renderer` pass
(54 tests)
- [x] App launches cleanly via direct Electron run
(`./node_modules/.bin/electron .`) — clean log, no errors

Note: `yarn test:e2e` fails on this branch, but it also fails on
`master` — pre-existing, unrelated to this change.

🤖 Generated with [Claude Code](https://claude.com/claude-code)