chore(docs+devops): cross-module doc sync + sprint archival moves + compose updates

Bundled pre-session doc + ops work:
- docs/modules/**: sync across advisory-ai, airgap, cli, excititor,
  export-center, findings-ledger, notifier, notify, platform, router,
  sbom-service, ui, web (architectural + operational updates)
- docs/features/**: updates to checked excititor vex pipeline,
  developer workspace, quick verify drawer
- docs top-level: README, quickstart, API_CLI_REFERENCE, UI_GUIDE,
  code-of-conduct/TESTING_PRACTICES updates
- docs/qa/feature-checks/: FLOW.md + excititor state update
- docs/implplan/: remaining sprint updates + new Concelier source
  credentials sprint (SPRINT_20260422_003)
- docs-archived/implplan/: 30 sprint archival moves (ElkSharp series,
  misc completed sprints)
- devops/compose: .env + services compose + env example + router gateway
  config updates

File-level granularity preserved.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/modules/findings-ledger/implementation_plan.md

@@ -9,7 +9,7 @@ Define the delivery plan for the Findings Ledger service, replay harness, observ
 
 ## Current host posture
 - `RiskEngine.WebService` now runs against PostgreSQL outside `Testing`; in-memory result stores are test-only.
-- `Findings.Ledger.WebService` non-testing hosts no longer fabricate scoring/webhook/runtime/VulnExplorer write state. Retired compatibility writes fail with truthful `501 problem+json`, while projection-backed reads remain served from persisted Findings state.
+- `Findings.Ledger.WebService` non-testing hosts no longer fabricate scoring/webhook/runtime/VulnExplorer write state. Retired compatibility writes fail with truthful `501 problem+json`, while explicit `Testing` harnesses inject the in-memory compatibility stores needed by focused integration tests.
 - The standalone `StellaOps.VulnExplorer.Api` host remains retired; no separate fake backend was reintroduced for legacy write flows.
 
 ## Near-term deliverables