118: PR #993 — freeing agent from harness

Where we left off

PR #880 (post #113) shipped Phase 0 of the Agent-vs-Harness terminology rollout: docs/glossary-agent-vs-harness.md, a renamed Role | Harness | Tasks table, and wording fixes across CLAUDE.md/README.md/SYNLYNK_GUIDE.md. But Phase 0 was docs-only by design — it named the distinction without touching any code. The CLI itself still had synlynk agent add/configure/run/list bound to execution-backend selection, which is exactly the concept Phase 0's glossary calls Harness, not Agent. Task #97 (Agent-roles-charters Phase 1) needed the real agent verb for role-identity onboarding (agent init/list/show/edit/disable) and couldn't claim it while the old harness-execution group still held it.

What moved the goalpost

Nothing strategic shifted — this is the mechanical unblock Phase 0 always implied but didn't do. The only real decision was whether a rename this central needed a deprecation shim. Pre-1.0, with a small and mostly-internal user base, the answer came out of a synlynk decide --panel claude,agy,codex,grok --record vote: unanimous 4/4 for a clean break, no shim (project-docs/decisions/2026-08-16-synlynk-s-cli-has-a-naming-collision-syn.md).

What this PR shipped

• synlynk agent add/configure/run/list → synlynk harness add/configure/run/list — the CLI verb group, its dest, and its help_parsers key all moved; the underlying cmd_agent_add/configure/run/list Python function names were left alone, since only the CLI-facing surface needed to change.
• No deprecation shim. Running the old synlynk agent add ... now fails with argparse's standard "invalid choice" error rather than silently routing to the new behavior — deliberate, per the spec's §4 breaking-change stance.
• Explicitly left untouched: dispatch <agent>, open <agent>, probe --agent, quota --agent, configure agent — all of these use "agent" in senses that don't collide (dispatch target, not the harness-execution verb group), so renaming them would have been scope creep against the actual naming collision.
• Freed the agent top-level verb for PR #1003 (Agent-roles-charters Phase 1), which landed immediately after and claimed it for synlynk agent init/list/show/edit/disable.

What this achieved

Closes the last blocker on Task #97's CLI surface. The terminology rollout is now consistent end-to-end: the glossary defines the split, the docs use the right words, and the CLI's own verb namespace no longer contradicts either.

The goal at the end of this PR

agent is free. Phase 1 of Agent-roles-charters (storage + CLI onboarding + dispatch integration) ships next, in the same session, using the verb this PR unblocked.