Harness foundation: INTENT, ADR-001, architecture, prototype adoption

- INTENT.md: three-layer model (blueprint/instance/harness), single
  shared runtime, never-become boundaries
- ADR-001 (accepted): DEC-2026-002 resolution — one harness repo for
  all projects; instances are declarative state in consuming repos
- docs/architecture.md: components, contracts (manifest, tool
  profiles, completion events, credential lanes), deployment shape
- agent_harness/: executor-worker prototype adopted and renamed
  (6/6 tests green); HARNESS-WP-0001 initial workplan (7 tasks)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

README.md

@@ -1,3 +1,26 @@
 # agent-harness
 
-A single shared runtime for agents created for the coulomb ecosystem.
+The single shared runtime for unattended agent instances in the Coulomb /
+Operational Knowledge ecosystem. Projects declare agents (manifest +
+`.kaizen/` state); this harness runs them — blueprint via kaizen-agentic,
+tasks via activity-core, compute via llm-connect, credentials via
+OpenBao/ops-warden, reporting to the Custodian State Hub.
+
+- Why and boundaries: [INTENT.md](INTENT.md)
+- Decision + architecture: [docs/adr/ADR-001](docs/adr/ADR-001-agent-harness-architecture.md),
+  [docs/architecture.md](docs/architecture.md)
+- Current work: [workplans/](workplans/)
+
+## Usage (prototype)
+
+```
+agent-harness run --task-file examples/task-hello-sandbox.json [--no-hub]
+agent-harness mail-scan --target-repo ~/binky-control
+```
+
+Runs exactly one task per invocation: persona bundle
+(`kaizen-agentic schedule prepare`) → bounded agentic session
+(cwd-pinned, hard tool allow-list, never pushes) → commit verification →
+State Hub progress event + task close.
+
+Tests: `PYTHONPATH=".:$HOME/llm-connect" python3 -m pytest tests/ -q`