feat(excititor+cli+web): VEX provider control plane — CLI + Web extensions (SPRINT_20260422_004)

Continues the SPRINT_20260422_004_Concelier_full_connector_control_plane
feature stream started in commit 5c1b59580 (Excititor provider management
endpoints + contracts + service + tests). Adds the CLI + Web surfaces on
top of that backend.

CLI (src/Cli/**):
- CommandHandlers + BackendOperationsClient extended with provider
  management calls
- ExcititorProviderSummary model added to the CLI's service models
- NonCoreCliCommandModule wires the new commands; tests updated
- TASKS.md entries synced

Web console (src/Web/StellaOps.Web/**):
- New vex-provider-catalog.component + vex-provider-management.api client
- advisory-source-catalog + advisory-vex-route-helpers extended to route
  users to the new VEX provider surface
- integration-hub.routes.ts registers the new route
- security-disposition-page.component.ts updated for the flow

Excititor/Concelier docs + contracts:
- docs/modules/excititor/operations/provider-control-plane.md — operator
  guide for the new control plane
- docs/modules/excititor/README.md + docs/modules/concelier/{README,
  connectors}.md — cross-links + refs
- ConfiguredAdvisorySourceService.cs — additional provider plumbing
- StellaOps.Excititor.WebService/TASKS.md synced

Sprint doc (docs/implplan/SPRINT_20260422_004_*.md) reflects the
in-flight progress.

This is external-stream work picked up during the 2026-04-22 session's
closeout — bundling it now so the working tree is clean and main stays
in sync with local feature-branch state.

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

docs/modules/excititor/README.md

@@ -40,6 +40,7 @@ Excititor converts heterogeneous VEX feeds into raw observations and linksets th
 - PostgreSQL (schema `vex`) for observation storage and job metadata.
 - Offline kit packaging aligned with Concelier merges.
 - Connector-specific runbooks (see `docs/modules/concelier/operations/connectors`).
+- Provider control plane inventory and readiness notes: [`operations/provider-control-plane.md`](./operations/provider-control-plane.md)
 - Ubuntu CSAF provenance knobs: [`operations/ubuntu-csaf.md`](operations/ubuntu-csaf.md) captures TrustWeight/Tier, cosign, and fingerprint configuration for the sprint 120 enrichment.
 
 ## Backlog references