feat(118): fakturownia single instance

Phase 118 complete:
- migration 20260512_000109 adds single global Fakturownia settings row
- FakturowniaIntegrationRepository simplified to one-instance API
- FakturowniaIntegrationController + edit view collapsed to one settings page
- Integrations hub shows Fakturownia as single instance
- Invoice config delegated flow always uses global integration_id

Note: shared routes/web.php and DOCS/* updates from Phase 118 are bundled
into the follow-up feat(121+122) commit because Phase 121/122 modified the
same files; hunk-level split was not performed.

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

.paul/phases/118-fakturownia-single-instance/118-01-SUMMARY.md

@@ -0,0 +1,52 @@
+# Phase 118 Plan 01 Summary - Fakturownia Single Instance
+
+## Status
+
+APPLY complete on 2026-05-12 13:47. Ready for UNIFY.
+
+## Implemented
+
+- Added `database/migrations/20260512_000109_fakturownia_single_instance.sql`.
+- Converted `FakturowniaIntegrationRepository` to one global settings row with `getSettings()`, `saveSettings()`, `getIntegrationId()`, `getCredentials()`, and compatibility wrappers.
+- Simplified `FakturowniaIntegrationController` to one settings page plus save/test actions.
+- Replaced Fakturownia multi-account list UI with a single configuration form and test panel.
+- Updated integrations hub to show Fakturownia as one instance.
+- Updated delegated invoice config save flow to always use the global Fakturownia `integration_id`.
+- Removed the invoice config account selector and replaced it with global Fakturownia status.
+- Updated `DOCS/DB_SCHEMA.md`, `DOCS/ARCHITECTURE.md`, and `DOCS/TECH_CHANGELOG.md`.
+- Updated `.paul/codebase/db_schema.md`, `.paul/codebase/architecture.md`, and `.paul/codebase/tech_changelog.md`.
+
+## Verification
+
+- PASS: `C:\xampp\php\php.exe -l` for changed PHP classes and `routes/web.php`.
+- PASS: `C:\xampp\php\php.exe -l` for changed PHP views.
+- PASS: static search found no active UI links for adding/deleting Fakturownia accounts; legacy `/new` and `/edit` routes redirect to the global settings page.
+- BLOCKED: `C:\xampp\php\php.exe bin\migrate.php` could not connect to local MySQL (`SQLSTATE[HY000] [2002]` target actively refused connection).
+- SKIPPED: PHPUnit is not available in `vendor/bin`.
+- SKIPPED: `sonar-scanner` is not available in PATH.
+
+## Environment Gaps
+
+- Run `C:\xampp\php\php.exe bin\migrate.php` after local MySQL/XAMPP is running.
+- Manually verify `/settings/integrations`, `/settings/integrations/fakturownia`, save/test Fakturownia settings, and local/delegated invoice config edit.
+- Live Fakturownia API test still requires valid credentials and network access.
+
+## Files Changed
+
+- `database/migrations/20260512_000109_fakturownia_single_instance.sql`
+- `src/Modules/Settings/FakturowniaIntegrationRepository.php`
+- `src/Modules/Settings/FakturowniaIntegrationController.php`
+- `src/Modules/Settings/IntegrationsHubController.php`
+- `src/Modules/Settings/InvoiceConfigRepository.php`
+- `src/Modules/Settings/InvoiceConfigController.php`
+- `src/Modules/Accounting/InvoiceService.php`
+- `resources/views/settings/fakturownia.php`
+- `resources/views/settings/fakturownia-edit.php`
+- `resources/views/settings/accounting-invoice-edit.php`
+- `routes/web.php`
+- `DOCS/DB_SCHEMA.md`
+- `DOCS/ARCHITECTURE.md`
+- `DOCS/TECH_CHANGELOG.md`
+- `.paul/codebase/db_schema.md`
+- `.paul/codebase/architecture.md`
+- `.paul/codebase/tech_changelog.md`