FDN-02/FDN-03/FDN-07/FDN-08: Migrations-Rollback, Objekt-Storage-Interface, go.sum-Fix, Observability

- FDN-02: Rollback-fähige Down-Migrationen (024-026), archivdms seed dev CLI
- FDN-03: internal/objectstore Interface + lokaler WORM-Treiber, signierte Download-URLs
- FDN-07: go.mod/go.sum vervollständigt (fehlender go-ldap/v3-Eintrag), CI-Pipeline (.gitea/workflows/ci.yml, bereits in FDN-01 committet) damit lauffähig
- FDN-08: Request-ID-Middleware, /metrics-Endpoint, Panic-Recovery, Login/Logout/Me technisches Logging inkl. Access-Log je Anfrage

internal/storage/migrations/026_accounting_api_keys.down.sql

@@ -0,0 +1,24 @@
+-- 026_accounting_api_keys.down.sql
+-- Rollback documentation for 026_accounting_api_keys.sql.
+-- Documentation only — archivdms has no migration runner; this file is the
+-- reviewed, copy-pasteable SQL an operator runs manually (psql) AFTER
+-- deploying a binary whose initSchema no longer creates the object, and
+-- inside an explicit transaction.
+--
+-- PRECONDITION: internal/storage/accounting_api_keys.go
+-- (Store.initAccountingAPIKeysSchema) must be removed from storage.New()
+-- first — otherwise the next process start recreates the table.
+--
+-- DATA LOSS: destroys all issued accounting API keys (hashes only, raw keys
+-- were never stored). Every buchhaltung integration using the Pull-API loses
+-- access and must be re-issued a new key. No GoBD document data is touched:
+-- accounting_api_keys holds credentials, not archived records. The audit
+-- entries referencing "key:<id>" survive in audit_log but their id becomes
+-- unresolvable — accept this only when the whole feature is being withdrawn.
+
+BEGIN;
+
+DROP INDEX IF EXISTS idx_accounting_api_keys_tenant;
+DROP TABLE IF EXISTS accounting_api_keys;
+
+COMMIT;