feat: node-scoped Networking operator page (#1603)

* feat: add node-scoped Networking operator page

Adds a Networking view with overview, topology, inventory, and findings.

Shared aggregate reads back the page; Resources keeps prune and redirects here.

Includes fail-closed network delete guards, operator docs, and /nodes/:slug/networking routing.

* fix: rename unused variable n to _n to satisfy no-unused-vars lint

* fix: keep top bar search clickable when nav grows

* feat: complete Compose-first Networking Phase 2 operator assistant

* fix: move networking action visibility helper out of component module

* feat(networking): complete Compose-first Networking operator page

Finish the node-scoped Networking page (Overview, Networks, Topology,
Findings) with design-system parity and correct finding semantics.

- Rebuild detail sheets on SystemSheet/SheetSection; align the tab band,
  masthead, and mobile tone with Fleet and Security.
- Encode the host-mode and exposure severity matrix; fix collision counts
  so intentional shared externals are not flagged; add one typed drift
  predicate shared by inventory, topology, badges, and overview counts.
- Preserve per-container attachments and IPs on topology node clicks;
  drawer-only click with an explicit logs action; ownership and boolean
  filters; bound large graphs before layout.
- Aggregate cached Compose Doctor findings into the Findings tab with
  honest source labels, structural merge and dedupe, staleness
  reconciliation, and a shared exposure-context helper both engines use.
- Networks tab: privacy-safe service search, precise ownership counts,
  schema v3 with version-2 adapters on every endpoint, pre-confirm delete
  reasons, and the shared sortable table with an internal scroll region.
- Interop: Fleet node-card networking signal with pending-intent
  navigation, stack-to-node backlink, and Dossier/Drift deep links.
- Enrich sanitized inspect with an allowlisted connected-container list;
  fetch topology once and filter client-side.
- Docs and tests across every new finding kind, adapter, and flow.

* fix(networking): correct drift count, exposure fail-soft, and inspect crash paths

Address code-review findings on the Networking page implementation:
- Fix the Overview drift count to use the shared drift-kind predicate instead
  of a hardcoded list that omitted external-network-missing.
- Gate Compose Doctor's unclassified-exposure and reverse-proxy-undocumented
  rules on exposure-context availability, so a DB read failure no longer
  fabricates findings (mirrors the live engine's existing fail-soft behavior).
- Guard the per-stack exposure-intent read in topology aggregation so a
  transient DB failure degrades to unknown intent instead of failing the
  whole response.
- Harden the network detail drawer against a partial inspect payload from an
  older remote node, and log the real error instead of a bare catch.
- Remove now-duplicated severity-rank and drift-kind helpers in favor of the
  shared modules; drop dead backend-only exports; widen the frontend schema
  version type to a plain number instead of casting past a literal type.
- Add coverage for the delete-guard precedence, the full host-mode severity
  matrix, the schema-2 compatibility adapter, and the sanitized connected-
  container allowlist; tighten two tests that were not exercising the
  behavior they claimed to.

* fix: add missing onOpenNodeNetworking prop to FleetView experimental test

The added required prop on FleetViewProps broke the merge-build when the
test file (on main but not on this branch) was compiled against the
updated FleetView interface.

backend/src/services/preflight/rules.ts

@@ -666,6 +666,8 @@ const exposureUnclassified: PreflightRule = {
   id: 'exposure-unclassified',
   run(ctx) {
     if (!ctx.model) return [];
+    // A read failure leaves every intent null; do not read that as "unclassified".
+    if (!ctx.exposureAvailable) return [];
     const publishing = ctx.model.services.filter(s => s.ports.length > 0);
     if (publishing.length === 0) return [];
     // Fire only when a publishing service is still effectively unclassified: a
@@ -712,6 +714,9 @@ const reverseProxyUndocumented: PreflightRule = {
   id: 'reverse-proxy-undocumented',
   run(ctx) {
     if (!ctx.model) return [];
+    // A read failure hides both the intent and any documented access URLs; do not
+    // interpret that absence as an undocumented reverse proxy.
+    if (!ctx.exposureAvailable) return [];
     // Already documented or intentionally reverse-proxied at the stack level.
     if (ctx.hasAccessUrls || ctx.stackIntent === 'reverse-proxy') return [];
     const findings: PreflightFinding[] = [];

backend/src/services/preflight/types.ts

@@ -125,6 +125,10 @@ export interface PreflightContext {
   accessUrlPorts: Set<number>;
   /** Whether the dossier records any access URL (gates the port-vs-documented rule). */
   hasAccessUrls: boolean;
+  /** False when the exposure context could not be read (a DB failure), distinct
+   *  from a genuinely unset intent. Gates the intent-interpretation rules so a
+   *  transient read failure does not fabricate unclassified/undocumented findings. */
+  exposureAvailable: boolean;
   /** True when this stack is the running Sencho instance on the node. */
   isSelfStack: boolean;
 }