Enhance logging in FdsSqlOptions and related classes

- Updated FdsSqlOptions to accept an optional ILogger parameter for improved error logging.
- Modified FdsMfr and FdsMfrClient classes to pass the logger instance to FdsSqlOptions.
- Added detailed error logging in various methods to capture SQL execution issues and file handling errors.
- Improved documentation for FdsSqlOptions to clarify logging behavior.
- Updated Archive class to log compression errors, enhancing traceability of failures.
- Adjusted project configuration to suppress specific warnings related to transitive dependencies.
- Added NuGet.config to define package sources for dependency management.
- Updated submodule references for OCORE and related projects.

Fuchs/Docs/Concepts/README.md

@@ -0,0 +1,66 @@
+# Concepts
+
+This folder holds **living design write-ups** of how a subsystem currently
+works: its moving parts, data flow, and how they fit together. Unlike
+[`../Decisions`](../Decisions/README.md), concept docs are **not** immutable
+— keep them in sync with the implementation as it evolves.
+
+## What belongs here
+
+"How does the notification pipeline work end to end" is a concept doc. "Why
+did we choose SignalR over polling for it" is a decision. A single feature
+area typically has one concept doc and may reference several decisions that
+shaped it.
+
+## File naming
+
+`kebab-case-topic.md` (no numbering — concepts aren't sequential events).
+
+## Required YAML frontmatter
+
+```yaml
+---
+status: Active            # Active | Deprecated
+lastUpdated: 2026-07-03
+applyTo:                  # glob(s) — files/areas this concept describes
+  - "Fuchs/Notifications/**"
+relatedDecisions:         # filenames in ../Decisions this concept implements
+  - "0001-domain-events-and-notification-triggers.md"
+---
+```
+
+**Agents must scan the YAML frontmatter of every file in this folder first**
+and only read the full body of concepts whose `applyTo` glob matches the
+files they're about to touch, or whose subject is otherwise clearly relevant.
+
+## Body template
+
+```markdown
+# Topic
+
+## Summary
+One paragraph: what this subsystem does and why it exists.
+
+## How it works
+The mechanics — components, data flow, sequencing. Diagrams (ASCII/mermaid)
+welcome where they clarify.
+
+## Key files
+Bullet list of the primary files/classes involved.
+
+## Related decisions
+Links to the ADRs in `../Decisions` that shaped this design.
+```
+
+## Rules
+
+- **Keep concepts current.** When you materially change how a documented
+  subsystem works, update its concept doc in the same change — don't let it
+  drift from the code.
+- **Create a concept doc for new non-trivial subsystems.** If you build
+  something a future agent would need a paragraph of context to safely
+  modify, write that paragraph here instead of making them re-derive it from
+  the diff.
+- Concepts describe **current** behavior. If something changes, edit the
+  doc in place — don't append a changelog inside it (git history is the
+  changelog).