feat(metrics): Implement scan metrics repository and PostgreSQL integration

- Added IScanMetricsRepository interface for scan metrics persistence and retrieval.
- Implemented PostgresScanMetricsRepository for PostgreSQL database interactions, including methods for saving and retrieving scan metrics and execution phases.
- Introduced methods for obtaining TTE statistics and recent scans for tenants.
- Implemented deletion of old metrics for retention purposes.

test(tests): Add SCA Failure Catalogue tests for FC6-FC10

- Created ScaCatalogueDeterminismTests to validate determinism properties of SCA Failure Catalogue fixtures.
- Developed ScaFailureCatalogueTests to ensure correct handling of specific failure modes in the scanner.
- Included tests for manifest validation, file existence, and expected findings across multiple failure cases.

feat(telemetry): Integrate scan completion metrics into the pipeline

- Introduced IScanCompletionMetricsIntegration interface and ScanCompletionMetricsIntegration class to record metrics upon scan completion.
- Implemented proof coverage and TTE metrics recording with logging for scan completion summaries.

docs/db/SPECIFICATION.md

@@ -1173,6 +1173,67 @@ CREATE INDEX idx_metadata_active ON scheduler.runs USING GIN (stats)
     WHERE state = 'completed';
 ```
 
+### 6.4 Generated Columns for JSONB Hot Keys
+
+For frequently-queried JSONB fields, use PostgreSQL generated columns to enable efficient B-tree indexing and query planning statistics.
+
+**Problem with expression indexes:**
+```sql
+-- Expression indexes don't collect statistics
+CREATE INDEX idx_format ON sbom_docs ((doc->>'bomFormat'));
+-- Query planner can't estimate cardinality, may choose suboptimal plans
+```
+
+**Solution: Generated columns (PostgreSQL 12+):**
+```sql
+-- Add generated column that extracts JSONB field
+ALTER TABLE scanner.sbom_documents
+ADD COLUMN bom_format TEXT GENERATED ALWAYS AS ((doc->>'bomFormat')) STORED;
+
+-- Standard B-tree index with full statistics
+CREATE INDEX idx_sbom_bom_format ON scanner.sbom_documents(bom_format);
+```
+
+**Benefits:**
+- **B-tree indexable**: Standard index on generated column
+- **Statistics**: `ANALYZE` collects cardinality, MCV, histogram
+- **Index-only scans**: Visible to covering indexes
+- **Zero application changes**: Transparent to ORM/queries
+
+**When to use generated columns:**
+- Field queried in >10% of queries against the table
+- Cardinality >100 distinct values (worth collecting stats)
+- Field used in JOIN conditions or GROUP BY
+- Index-only scans are beneficial
+
+**Naming convention:**
+```
+<json_path_snake_case>
+Examples:
+  doc->>'bomFormat'     → bom_format
+  raw->>'schemaVersion' → schema_version
+  stats->>'findingCount'→ finding_count
+```
+
+**Migration pattern:**
+```sql
+-- Step 1: Add generated column (no lock on existing rows)
+ALTER TABLE scheduler.runs
+ADD COLUMN finding_count INT GENERATED ALWAYS AS ((stats->>'findingCount')::int) STORED;
+
+-- Step 2: Create index concurrently
+CREATE INDEX CONCURRENTLY idx_runs_finding_count
+ON scheduler.runs(tenant_id, finding_count);
+
+-- Step 3: Analyze for statistics
+ANALYZE scheduler.runs;
+```
+
+**Reference implementations:**
+- `src/Scheduler/...Storage.Postgres/Migrations/010_generated_columns_runs.sql`
+- `src/Excititor/...Storage.Postgres/Migrations/004_generated_columns_vex.sql`
+- `src/Concelier/...Storage.Postgres/Migrations/007_generated_columns_advisories.sql`
+
 ---
 
 ## 7. Partitioning Strategy