Manage timeline activity types in application settings (#24662)

## Summary

- list every timeline activity type as its own row in the application
Content tab, matching command menu items and other syncable entities
- give each installed activity type its own detail route, breadcrumbs,
metadata table, and standard settings controls
- use the existing full-row settings toggle card for timeline visibility
and the standard reset section for restoring application defaults
- keep manifest-preview activity types as individual read-only Content
rows
- remove the bespoke aggregate management page, list card, inline row
toggles, and overflow reset menu
- keep record timeline filtering in its existing dropdown pattern

## Stack

Base: `main`

## Review follow-up

- align timeline activity type navigation with the existing
command-menu-item detail flow
- track concurrent mutations independently by timeline activity type ID
- hide reset for the workspace custom application and fail closed while
workspace metadata is unavailable
- wait for reset mutation responses instead of optimistically inventing
manifest defaults
- keep each application settings type in its own file

## Validation

- PASS: `npx nx build twenty-shared --skip-nx-cache`
- PASS: `npx nx build twenty-sdk --skip-nx-cache`
- PASS: `npx tsgo -p packages/twenty-front/tsconfig.json --noEmit`
- PASS: focused Jest coverage — 2 suites, 6 tests
- PASS: `npx nx lint twenty-front --skip-nx-cache` — 0 warnings, 0
errors; formatting clean
- PASS: `npx nx lint twenty-shared --skip-nx-cache` — 0 warnings, 0
errors; formatting clean
- PASS: `git diff --check`

No translation catalogs were regenerated.