feat: migrate DB error logging onto the generic OCORE MultiLogger SQL sink

Retires Fuchs_intranet.debug_log() and every direct EXECUTE [dbo].[fds__admin_logdebug]
call in favor of a single path: ILogger. A new SQL log sink (OCORE.MultiLogger.SqlLoggerProvider,
gated by Fuchs:Logging:SqlSink:Enabled, default on) mirrors every _logger.LogWarning/-Error/
-Critical call into [dbo].[fds__debuglog] via a new fds__admin_logdebug_ext proc, at Warning+.

- Program.cs registers the sink and RequestLogScopeMiddleware (request id/path/authenticated
  user, pushed after UseAuthentication) so every log line in a request — including ones written
  deep inside OCORE's SQL helpers — is attributed automatically.
- FIS_SQLOptions, IntranetController.Do's catch-all, PdfPreviewAsync, and the banking-upload
  handlers now log once, with an explicit EventId preserving the exact CodeReference text the
  retired debug_log() calls used to write, so existing dashboards/queries over fds__debuglog
  keep working unchanged.
- Fuchs_DataService/FdsMfr.cs's FdsSqlOptions had the identical double-write hazard (it's hosted
  in the same process per ADR 0010) — the original 2026-09-16 log review's mfr__getSchema/
  fds__getUpdateableRequests deadlock rows came from exactly this class. Fixed the same way.
- fds__debuglog gains LogLevel/Machine/Category/Account/AuthUser/IsDebug columns; the legacy
  fds__admin_logdebug proc is left in place unused, not dropped.
- FdsDebug.DebugLog (Fuchs_DataService's other ~9 call sites) deliberately left on its direct
  DB-write path — no ILogger call sits alongside it there, so no duplication risk today.

See ADR 0024 (supersedes 0023) and Docs/Concepts/error-logging-pipeline.md.

New tests: ErrorLoggingTests (FIS_SQLOptions), FdsSqlOptionsTests, RequestLogScopeMiddlewareTests.
694/694 pass (the 4 PdfPipelineTests failures seen under full-suite parallel runs are a
pre-existing, unrelated PdfSharp global-font-resolver test-isolation flake — they pass both
individually and in most full-suite runs).

Bumps the OCORE submodule to 3137b56 (SQL sink hardening: redaction matches short fragments
as whole identifier segments, per-entry-tolerant serialization, lazy dataSerialized, opt-in
SqlLoggerOptions.IncludeCategory, LogEntry.Category/AuthUser capture).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Fuchs/Docs/Decisions/0023-user-action-failures-persisted-to-db-log.md

@@ -1,13 +1,20 @@
 ---
-status: Accepted
+status: Superseded
 date: 2026-09-16
 applyTo:
   - "Fuchs/Controllers/**"
   - "Fuchs/code/FuchsIntranet.cs"
   - "Fuchs/js/intranet/**"
-supersededBy: ""
+supersededBy: "0024-multilogger-sql-log-sink.md"
 ---
 
+> **Superseded by [0024](0024-multilogger-sql-log-sink.md).** The explicit `Fuchs_intranet.debug_log` /
+> `fds__admin_logdebug` DB write this decision introduced was retired the same day, once
+> [0024](0024-multilogger-sql-log-sink.md) made `ILogger` itself the single path to the DB log
+> (`fds__admin_logdebug_ext`, same `fds__debuglog` table). Keeping both would have double-written
+> every row. The frontend/`x-ocms-desc`/`EncodeResponseDescription`/preview-timeout decisions below
+> are unaffected and still in force — only the *DB write mechanism* changed.
+
 # 0023 — Failures of user actions are persisted to `fds__admin_logdebug`, with the SQL and a readable description
 
 ## Context
@@ -36,7 +43,10 @@ rarely reachable. Reviewing the 2026-09-16 production extract of that table show
   `Unhandled exception in Do {fn}/{id}` with route, user and the form *field names* (never
   values — they can carry tokens/PII); the PDF-preview endpoints go through a shared guard
   (`IntranetController.PdfPreviewAsync`) that logs `PDF preview failed (endpoint)` with
-  ref/user/duration, counts `fuchs.pdf.previews{outcome}` and toasts the user.
+  ref/user/duration, counts `fuchs.pdf.previews{outcome}` (`success`/`gone`/`failure` — an
+  expired-draft `410` from inside `render()` is its own `gone` outcome, not `success`, since
+  it is not the render failure this guard exists to catch) and, for an authenticated caller,
+  toasts the user.
 - **A 500 carries its message in the `x-ocms-desc` header** (`ServerError(msg)` →
   `EncodeResponseDescription`: percent-encoded ASCII, spaces as `%20` because the client
   maps `+` to space before `decodeURIComponent`). Handlers that return a 500 should pass a
@@ -53,7 +63,10 @@ rarely reachable. Reviewing the 2026-09-16 production extract of that table show
   added to hot/success paths (see [0003](0003-structured-diagnostic-logging.md) on the cost
   of DB logging).
 - `x-ocms-desc` is user-facing: messages must be German, short, and free of secrets. The
-  innermost exception text is acceptable for an internal intranet audience.
+  innermost exception text is acceptable for an authenticated intranet user, but some
+  preview endpoints (`req/idoc`, `inv/rdoc`, `inv/rdocn`, `rem/idoc` — see `_allowedGet`
+  in `IntranetController.cs`) are reachable without authentication; `PdfPreviewFailureMessage`
+  omits the exception detail for those callers and falls back to the generic message.
 
 ## Alternatives considered
 - **Enable `FuchsLoggerProvider.DatabaseLoggingEnabled`** so every `ILogger` error lands in