Add determinism tests for verdict artifact generation and update SHA256 sums script

- Implemented comprehensive tests for verdict artifact generation to ensure deterministic outputs across various scenarios, including identical inputs, parallel execution, and change ordering.
- Created helper methods for generating sample verdict inputs and computing canonical hashes.
- Added tests to validate the stability of canonical hashes, proof spine ordering, and summary statistics.
- Introduced a new PowerShell script to update SHA256 sums for files, ensuring accurate hash generation and file integrity checks.

docs/technical/architecture/data-isolation.md

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+# Data isolation model (PostgreSQL)
+
+StellaOps uses PostgreSQL as the canonical durable store. Isolation is achieved by:
+- One schema per service (clear ownership boundaries).
+- Tenant identifiers on all tenant-scoped records (enabling row-level strategies where required).
+- Append-only patterns for specific evidence stores to preserve replayability.
+
+## Schema ownership map
+
+| Schema | Owner (primary) | Data class |
+| --- | --- | --- |
+| `authority` | Authority | Identity, clients, keys, auth audit trails. |
+| `scanner` | Scanner | Scan manifests, triage, scan result metadata. |
+| `vuln` | Concelier | Advisory raw documents, linksets, observations. |
+| `vex` | Excititor | VEX raw statements and consensus state. |
+| `scheduler` | Scheduler | Job orchestration state. |
+| `notify` | Notify | Notifications state and delivery history. |
+| `policy` | Policy | Exceptions, policy snapshots, unknown tracking. |
+| `orchestrator` | Orchestrator | Workflow orchestration state. |
+
+## Where to find authoritative schemas
+
+This document is descriptive. The authoritative contract is:
+- Module dossiers and migration notes under `docs/modules/<module>/`
+- Database schema reference: `docs/11_DATA_SCHEMAS.md`