Add ZIP-wrapped CAMT parsing and real bank file tests

- Support parsing camt.052 ZIP archives in CamtParser and BankingService
- Add CamtZipParserTests for ZIP parsing (single/multi/malformed/empty cases)
- Add CamtRealFileTests: integration tests for real bank exports (ZIP, XML, CAMT, MT940, STA) in git-ignored test data dir
- Update .gitignore and add README.md for test data usage
- Copy test data files in Fuchs.Tests.csproj; add .gitkeep
- Refactor BankingService CAMT mapping logic
- Overhaul connection string config: use {username}/{password} tokens, resolve from secrets at runtime, update appsettings and Key Vault keys

Fuchs/appsettings.json

@@ -5,8 +5,10 @@
     "CacheFilePath": "secrets.cache",
     "SyncIntervalHours": 6,
     "ManagedSecretKeys": [
-      "ConnectionStrings--ocms-ConnectionString",
-      "ConnectionStrings--fuchs-fds-ConnectionString",
+      "ConnectionStrings--ocms-username",
+      "ConnectionStrings--ocms-password",
+      "ConnectionStrings--fuchs-fds-username",
+      "ConnectionStrings--fuchs-fds-password",
       "Fuchs--SMS-APIKey",
       "Fuchs--Mailer--Token",
       "Fuchs--fuchs-captcha-TOTP",
@@ -21,8 +23,12 @@
   },
   "AllowedHosts": "*",
   "ConnectionStrings": {
-    "ocms_ConnectionString": "MANAGED_BY_KEYVAULT",
-    "fuchs_fds_ConnectionString": "MANAGED_BY_KEYVAULT"
+    "ocms_ConnectionString": "Server=DB_SERVER;Database=ocms;User Id={username};Password={password};TrustServerCertificate=True;",
+    "fuchs_fds_ConnectionString": "Server=DB_SERVER;Database=fuchs_fds;User Id={username};Password={password};TrustServerCertificate=True;",
+    "ocms_username": "MANAGED_BY_KEYVAULT",
+    "ocms_password": "MANAGED_BY_KEYVAULT",
+    "fuchs_fds_username": "MANAGED_BY_KEYVAULT",
+    "fuchs_fds_password": "MANAGED_BY_KEYVAULT"
   },
   "Fuchs": {
     "ocms_guid": "00094b8f-a822-4e9c-b627-87802f93fca8",