feat(recycle-bin): soft delete + restore for master data

Accidental admin deletes of users/roles/subscriptions/plans/tariffs were
hard and unrecoverable. Now they soft-delete into a recycle bin.

Schema (migration 0012): nullable deleted_at + deleted_by on users, roles,
subscriptions, subscription_plans, tariffs. Additive ADD COLUMN; verified
against a copy of the live DB.

Backend: each resource's DELETE route STAMPS instead of removing; every
catalog list filters deleted_at IS NULL. New recycle-bin module + routes
(GET /api/recycle-bin, POST .../restore, DELETE .../:id purge) gated on a
new recyclebin:read/update/delete permission. A 6-hourly + startup sweep
auto-purges items older than RECYCLE_BIN_RETENTION_DAYS (default 30; 0 =
forever).

Invariants: soft-deleted users can't log in (login rejects deleted_at;
no-lockout counts live admins only); a soft-deleted subscription doesn't
open the barrier; plans are versioned so a delete stamps all versions of
the plan_id (bin shows one item); username/role-name UNIQUE spans deleted
rows so reuse returns a clear 409 pointing at the bin; restore doesn't
auto-cascade a dangling role (guard resolves missing role to empty perms).
The signed append-only ledger is OUT of scope (no delete path).

Web: a Recycle bin tab under Setup (RecycleBin.tsx) with Restore/Purge +
purge confirm; api client + i18n (sq + en parity).

Tests: recycle-bin.test.ts (9 unit) + recycle-bin-routes.test.ts (4
integration: delete -> can't-login -> restore -> login, purge, gating,
409 reuse). server 103/103; build+lint+test 19/19.

Wiki: new concepts/soft-delete.md; local-jwt-auth + index + log updated.

Claude-Session: https://claude.ai/code/session_01Xcm6ikLgGoCxxHrxtjkk5V

packages/db/drizzle/0012_soft_delete.sql

@@ -0,0 +1,19 @@
+-- Soft delete (recycle bin) for accidental hard-deletes of master data. Adds a nullable
+-- `deleted_at` (ISO-8601; null = live) + `deleted_by` (the admin user id) to the mutable
+-- master-data tables. A DELETE now stamps these instead of removing the row; restore
+-- clears them; an admin purge (or the retention sweep) does the real DELETE. The signed
+-- append-only ledger is NOT touched — it has no delete path and is out of scope here.
+--
+-- All additive ALTER ADD COLUMN — backward-compatible (existing rows: deleted_at null =
+-- live). SQLite ADD COLUMN is in-place. Subscription PLANS are versioned (many rows per
+-- plan_id); a soft-delete stamps every version row of that plan_id together.
+ALTER TABLE `users` ADD `deleted_at` text;--> statement-breakpoint
+ALTER TABLE `users` ADD `deleted_by` text;--> statement-breakpoint
+ALTER TABLE `roles` ADD `deleted_at` text;--> statement-breakpoint
+ALTER TABLE `roles` ADD `deleted_by` text;--> statement-breakpoint
+ALTER TABLE `subscriptions` ADD `deleted_at` text;--> statement-breakpoint
+ALTER TABLE `subscriptions` ADD `deleted_by` text;--> statement-breakpoint
+ALTER TABLE `subscription_plans` ADD `deleted_at` text;--> statement-breakpoint
+ALTER TABLE `subscription_plans` ADD `deleted_by` text;--> statement-breakpoint
+ALTER TABLE `tariffs` ADD `deleted_at` text;--> statement-breakpoint
+ALTER TABLE `tariffs` ADD `deleted_by` text;