feat(mileage): surface Körjournal in the nav behind a settings toggle (#1540)

* feat(mileage): surface Körjournal in the nav behind a settings toggle

The /mileage page shipped hidden: the route works but no nav row points at
it. Add company_settings.mileage_enabled (mirroring dimensions_enabled) with
a switch in Fönster -> Bokföring, and show the Arbeta nav row when the toggle
is on OR the company already has mileage_trips rows, the same hybrid gate as
webshop orders, so trips created via API/MCP can never become invisible
underlag. UI visibility only, never load-bearing for correctness.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* fix(migrations): move mileage_enabled migration after already-applied 20260812153208

origin/main merged in 20260812153208 which prod has already applied; a new
file sorting before it risks an out-of-order db push abort.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

types/index.ts

@@ -442,6 +442,10 @@ export interface CompanySettings {
   // load-bearing for correctness. Free tier (founder decision 2026-07-02).
   dimensions_enabled: boolean
 
+  // Körjournal (mileage log): UI-visibility toggle only, never load-bearing
+  // for correctness. The nav row also shows when mileage_trips rows exist.
+  mileage_enabled: boolean
+
   // Salary payments (migration 20260508120000 + 20260703190000).
   // preferred_payment_format defaults to 'pain001' — Bankgirot Lön is
   // retired by the banks during 2026.