[dzungtr]

Closes #198

What

• Uniform deprecation banner in operator/README.md, runtime/README.md, task-service/README.md naming the greenfield successor (Greenfield KAPE successor: agent-first orchestration on OpenShell sandboxes #150) and the re-role intent (deprecated ≠ deleted).
• runtime/ and task-service/ had no README before; these are new banner READMEs (additions only).
• CONTEXT.md glossary: _Deprecated (v1 platform)_ annotations on Operator (Kape* materialisation), Handler runtime, and Task.

Acceptance

• Banners + successor pointer in all three READMEs
• CONTEXT.md marks Kape* materialisation, Handler runtime, task-service concepts
• Zero deletions, zero functional change (docs-only diff, +15/-0)
• Handoffs row recorded in spec M2 Epic 1 PRD: session-layer foundation — durable event log, FSM, session/agent model #194

[dzungtr]

Merging with CI gate waived: the Operator envtest suite failure is pre-existing on main — operator/test/integration/suite_test.go:87-88 passes k8sadapters.NewStatefulSetAdapter and cfgLoader into reconcilehandler.NewToolReconciler, which since #147/#145 requires a ports.QdrantClusterPort (EnsureQdrantCluster) and a record.EventRecorder (AnnotatedEventf). This PR is docs-only (+15/-0) and cannot affect that suite. The envtest fix is tracked separately.