v0.8.1 — first-run fixes from a fresh-user walkthrough

First-run fixes from a documented-paths-only walkthrough: a fresh agent followed the README and docs on a clean machine with no source access, and everything it stumbled on is fixed.

Onboarding

• agentstack init works on a clean machine. With no supported CLIs to import, it now scaffolds a commented starter manifest (worked server example + next steps) instead of writing nothing — previously every other command said "run agentstack init" while init itself declined, a circular dead end for first-time users.
• apply explains skills. Skills activate through profiles (agentstack use <profile> --write), never through apply — that's by design, and apply now says so instead of silently ignoring manifest skills.
• use --write summary is honest when skills were written but no CLI binaries were detected (no more "activated on 0 target(s)" under a ✓ skills line).

Docs

• README opening reconciled with the tool's own agentstack setup hint; skills-need-profiles stated up front; pointer to the zero-files trust-gate path from the top.
• agentstack connect --all --write shown correctly (bare connect errors).
• Running agentstack lock re-gates trust (new pins = new consent) — now documented where you'll hit it.
• Manifest relative paths anchor at .agentstack/ (a skill's path = "./skills/x" lives at .agentstack/skills/x); a server's cwd is the documented exception (project root).

Embedded skill

The bundled using-agentstack skill (served to agents over the control plane) now covers the runtime half: the trust gate (agents must never run agentstack trust themselves — it's the human consent gate), reading two-layer policy denials, compact vs transparent modes, audit --calls, and analyze.

For what the walkthrough confirmed working exactly as documented — trust gate, both policy layers, transparent mode, call log, library + lock — see v0.8.0.