Add onboarding-tester agent (docs-only fresh-adopter)

Global fleet agent that walks a product's published docs as a literal
newcomer, never reading its source, reports every doc gap, and emits a
publishable walkthrough only on a fully clean run. First instantiation:
keysat SDK integration. Register in fleet list, log ROADMAP item 9 and a
Current-state note, resolve the originating inbox item, and capture two
follow-ups (Path 2 payment demo, operator-onboarding agent).

AGENTS.md

@@ -20,7 +20,7 @@ file added under `adapters/` is live immediately — no per-file linking:
   `/handoff`, `/full-eval`, `/capture`, `/triage`, `/roundup`, `/new-project`, `/design`).
 - `~/.claude/agents` → `adapters/claude/agents/` — global subagents (reviewer, evaluator,
   security-auditor, doc-auditor, exerciser, researcher, janitor, portability-checker,
-  start9-spec-checker, design-checker).
+  start9-spec-checker, design-checker, onboarding-tester).
 - `~/.claude/CLAUDE.md` → `how-i-work.md` — my universal preferences, loaded every session.
   (Distinct from this repo's *root* `CLAUDE.md`, which → `AGENTS.md`: same filename, different
   scopes — global preferences vs. this repo's orientation.)
@@ -106,10 +106,19 @@ should carry this so any vendor's agent surfaces pending items at session start:
   pill-radius blockers + token gaps) → in keysat ROADMAP **and** captured to `INBOX.md` (P2).
 - Also this session: deleted `start-os` (it was a pristine external Start9 upstream clone — none
   of our work); fixed `premier-gunner`'s stale "set a real password" next-step (already set).
+- **Onboarding-tester agent built (this session).** Global docs-only adopter agent
+  (`guides/onboarding-tester.md` + wrapper, live via the `adapters/` symlink): walks a product's
+  published docs as a literal newcomer, **never reading the product's source** (needing to is
+  itself a finding), reports doc gaps (Blocker/Stumble/Nit + the one-line fix), and on a **fully
+  clean run** emits a publishable "all it took was X, Y, Z" walkthrough for marketing. Generic;
+  first target is keysat SDK integration (gate `proof-of-work` behind a license) under keysat's new
+  least-privilege `merchant-onboard` scoped key (keysat commit `d5885d1`). **Pending:** wire the
+  keysat-side harness (two disposable containers + key minting + docs-corpus URLs) and run it live —
+  built next in a keysat session. ROADMAP item 9.
 - **Next steps:** (1) **backfill design into recaps.cc / recap** — the extract→reconcile
   **Case B** path (organic aesthetic, no prior guidelines), the on-ramp not yet tested;
   (2) cross-repo quality-gate standard + `/harden` (ROADMAP item 1); (3) non-git-folder sweep
-  under `~/Projects` (~13).
+  under `~/Projects` (~13); (4) wire + run the keysat `onboarding-tester` harness (ROADMAP item 9).
 - **Open:** a *fresh* Claude Design run is still needed to confirm what its export actually
   contains and tune Phase-C distillation — keysat was an import of a prior artifact, not a live
   export; the related Field-note seeds stay marked "confirm on first live run."