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/024_ocr_words.down.sql

@@ -0,0 +1,27 @@
+-- 024_ocr_words.down.sql
+-- Rollback documentation for 024_ocr_words.sql.
+-- Documentation only — archivdms has no migration runner; run manually via
+-- psql after deploying a binary whose initSchema no longer creates the table.
+--
+-- PRECONDITION: Store.initOCRWordsSchema must be removed from
+-- Store.initSchema (internal/storage/documents.go) and every caller of
+-- ReplaceOCRWords / the word-box read path must be gone first — otherwise
+-- the next process start recreates the table.
+--
+-- DATA LOSS: ocr_words is a DERIVED index over each document's OCR run, not
+-- an original record. Dropping it loses no GoBD-relevant data; the word boxes
+-- are fully regenerable by re-running OCR
+-- (`archivdms documents reprocess-all`). Only the highlight/overlay feature
+-- degrades until then.
+--
+-- WORM: no archived file in store/ is touched; the FK to documents is only
+-- consumed here (ON DELETE CASCADE), never the other way round, so dropping
+-- this table cannot cascade into documents.
+
+BEGIN;
+
+DROP INDEX IF EXISTS idx_ocr_words_word_text;
+DROP INDEX IF EXISTS idx_ocr_words_document;
+DROP TABLE IF EXISTS ocr_words;
+
+COMMIT;