feat: config portability with generic entity resolver framework

Full configuration export/import system for Homarr with excellent DX:
- Export/import boards, apps, integrations (with re-encrypted secrets),
  users (with bcrypt hashes), groups (with permissions and memberships),
  search engines, and server settings
- Homepage services.yaml import with widget-type mapping
- Generic resolveEntities() utility eliminates per-entity boilerplate
- Declarative entity-fields.ts: adding a new user preference requires
  only one line change (no export/import/schema edits needed)
- User schema uses .catchall(z.unknown()) for forward-compatible prefs
- groupByKey() utility replaces manual Map-building
- CONFIG_ENTITY_KEYS as single source of truth for entity metadata
- Reuse existing entities (apps by name+icon+href, integrations by
  kind+name+url, users by email, groups by name, boards by name)
- Skip duplicates with warnings rather than failing
- Onboarding flow skips user creation step when config includes users
- Reuse existing admin group during onboarding after config import

docs/config-portability.md

@@ -1,66 +0,0 @@
-# Config Portability & Import/Export
-
-## New features
-
-### Full Configuration Export & Import (`/manage/tools/import-export`)
-
-New dedicated tool page under **Manage → Tools → Import / Export** with:
-
-- **Export Full Configuration** — downloads a JSON bundle containing all boards, apps, integrations (with encrypted secrets), server settings, search engines, and groups. The encryption key is embedded so secrets can be restored on another instance. A popover with warnings and a preview summary is shown before download.
-- **Import Homarr Configuration** — upload a previously exported JSON file. Shows a compatibility check, a preview of what will be created / reused / skipped / updated, then imports everything transactionally. Server settings that haven't changed are no longer counted as "Will update".
-- **Import Homepage services.yaml** — parse a Homepage dashboard `services.yaml`, resolve `{{HOMEPAGE_VAR_*}}` template variables with a form, and create a board with apps and integrations.
-- **Docker Label Discovery** — scan running Docker containers for `homarr.*` or `homepage.*` labels and sync discovered services into boards. Moved here from the Docker page. Discovery is now triggered manually via the **Scan** button (the background cron job was removed).
-
-### Onboarding: Import Homarr JSON
-
-The onboarding flow (`/init`) now offers a third option:
-
-- **Import Homarr configuration (.json)** — alongside "Start from scratch" and "Import from Homarr before 1.0"
-- Uses the same preview panel (compatibility, create/reuse/skip/update counts) as the admin import tool
-- Boards are created with `creatorId: null` (no admin user exists yet at this step)
-
-### Board Portability package (`@homarr/board-portability`)
-
-New package with:
-
-- **Schema** (`homarrConfigBundleSchema`) — v2.0 bundle format with boards, apps, integrations (encrypted secrets), server settings, search engines, groups
-- **Export** — `exportFullConfigAsync`, `previewExportFullConfigAsync`, `serializeBoard`, `toJson`
-- **Import** — `importFullConfigAsync`, `previewImportFullConfigAsync`, `planFullConfigImport`, `parseBundle`, `matchApps`
-- **Homepage** — `parseServicesYaml`, `prepareHomepageImport`, `extractHomepageEnvVariables`, `replaceHomepageEnvVariables`, widget type mapping
-- **Compat** — `assessBundleCompatibility`, `parseConfigBundleJson`, format version validation
-
-### Docker Label Discovery (`@homarr/docker/discovery`)
-
-- `listDiscoveredContainersAsync` — scans Docker hosts for labeled containers
-- `parseContainerLabels` — parses `homarr.*` and `homepage.*` label sets
-- `syncDiscoveredServicesAsync` — creates/updates apps and board items from discovered services
-- `docker_app_source` table + migrations (SQLite/MySQL/PostgreSQL) — tracks which apps were created by discovery
-
-### CLI commands (`@homarr/cli`)
-
-- `boards list` — list all boards
-- `boards export` — export a board bundle by name
-
-### Export/Import modals (`@homarr/modals-collection`)
-
-- `ExportBoardModal` — single-board export
-- `ImportBundleModal` — single-board bundle import
-- `ImportHomepageModal` — Homepage services.yaml import (also used from board card menu)
-
-### Example docker-compose (`examples/docker-compose.yml`)
-
-Media stack (Sonarr, Radarr, Prowlarr, qBittorrent, Jellyfin, Overseerr) with `homarr.*` labels for discovery.
-
-## Bug fixes
-
-- **xterm.js crash** — removed `@xterm/addon-canvas` which is incompatible with `@xterm/xterm` v6 (canvas renderer was removed upstream). The logs terminal now uses the built-in DOM renderer. This fixed `TypeError: can't access property "onShowLinkUnderline", this._linkifier2 is undefined` that appeared when navigating between pages.
-- **Homepage env variable editing** — fixed `MISSING_MESSAGE: field.envVariables.label` (wrong i18n namespace in import-homepage-card) and `TypeError: can't access property "value", t.currentTarget is null` (React 19 null `currentTarget` in onChange handlers).
-
-## Changes
-
-- **Docker Label Discovery** is no longer a background cron job. The `discoveryEnabled` server setting was removed. Discovery is now triggered manually from the Import/Export page.
-- **Docker settings form** no longer shows the "Enable Docker label discovery" toggle.
-- **Import/Export sidebar entry** added under Manage → Tools.
-- **Board card menu** — removed bundle/homepage import options from the boards create menu (they live in Import/Export now).
-- **Server settings preview** compares serialized values and only counts settings that actually differ (re-importing the same export shows 0 updates).
-- **Shared UI components** — `ConfigImportPreviewPanel` and `ConfigSummaryList` extracted to `~/components/config-import/` for reuse between the admin tool and onboarding.