Complete WP-0006 through WP-0009: registry expansion, catalog, graph, tests

Register six new capabilities (12 total), add searchable catalog UI and graph
explorer, introduce pytest suite with CI fail-on-warnings, and close gap
analysis priorities 13 and 16. WP-0010 remains backlog for network federation.

registry/capabilities/capability.feature-control.visibility.md

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+---
+id: capability.feature-control.visibility
+name: Feature Visibility Control
+summary: Control whether features are visible or hidden for subjects without changing underlying entitlement or authorization.
+owner: feature-control
+status: draft
+domain: helix_forge
+tags: [feature-control, visibility]
+
+maturity:
+  discovery:
+    current: D4
+    target: D5
+    confidence: medium
+    rationale: Bounded as distinct from evaluation and rollout in feature-control domain.
+  availability:
+    current: A2
+    target: A4
+    confidence: low
+    rationale: May share SDK artifacts with evaluate but is not separately exposed as API.
+
+external_evidence:
+  completeness:
+    level: C2
+    name: Partial
+    confidence: low
+    basis: scope_vs_intent_and_consumer_expectations
+    satisfied_expectations:
+      - visibility distinguished from evaluation in registry model
+    broken_expectations:
+      - no standalone visibility API documented separately
+    out_of_scope_expectations:
+      - authorization policy decisions
+  reliability:
+    level: R1
+    confidence: low
+    basis: consumer_quality_signals
+    known_reliability_risks:
+      - easily conflated with evaluate capability
+
+discovery:
+  intent: Govern feature visibility separately from availability evaluation and rollout staging.
+  includes:
+    - hide/show feature UI or capability surfaces
+    - visibility rules per subject context
+  excludes:
+    - entitlement ownership
+    - rollout percentage control
+  use_cases: []
+
+availability:
+  current_level: A2
+  target_level: A4
+  current_artifacts:
+    - feature-control/packages/feature-control-sdk
+  consumption_modes:
+    - source module
+
+relations:
+  depends_on:
+    - capability.feature-control.evaluate
+  related_to:
+    - capability.feature-control.rollout
+
+consumer_guidance:
+  recommended_for:
+    - planning visibility behavior separate from on/off evaluation
+  not_recommended_for:
+    - authorization or billing gating
+  known_limitations:
+    - implementation may be bundled with evaluate SDK today
+---
+
+# Feature Visibility Control
+
+Visibility governs whether a feature surface appears, distinct from whether the
+feature is enabled for a subject.