Add tests for SBOM generation determinism across multiple formats

- Created `StellaOps.TestKit.Tests` project for unit tests related to determinism.
- Implemented `DeterminismManifestTests` to validate deterministic output for canonical bytes and strings, file read/write operations, and error handling for invalid schema versions.
- Added `SbomDeterminismTests` to ensure identical inputs produce consistent SBOMs across SPDX 3.0.1 and CycloneDX 1.6/1.7 formats, including parallel execution tests.
- Updated project references in `StellaOps.Integration.Determinism` to include the new determinism testing library.

docs/ui/exception-center.md

@@ -1,18 +1,5 @@
-# Exception Center UI (stub)
+# Archived: Exception Center
 
-> Status: BLOCKED — waiting on UI assets/payloads and accessibility guidance (DOCS-EXC-25-005).
+This page was consolidated during docs cleanup.
 
-## Outline
-1. Overview + imposed rule banner
-2. Navigation and badges
-3. Workflow walkthrough (create, approve, reject)
-4. Accessibility/keyboard shortcuts
-5. Offline considerations (asset packaging, deterministic captures)
-6. Troubleshooting
-
-## Determinism
-- Hash captures/payloads into `docs/ui/SHA256SUMS` once provided.
-- Prefer command-rendered outputs where possible; if screenshots are used, store under `docs/ui/assets/exception-center/` with hashes.
-
-## Assets
-- Screenshots/command-rendered outputs (when provided) will live under `docs/ui/assets/exception-center/` and be hash-listed in `docs/ui/SHA256SUMS`.
+- Canonical Console guide: `docs/15_UI_GUIDE.md`