docs(lanes): design F3b — ccam skills install (E)

Found auditing E1-F3a for Shipyard parity: .claude/skills/ship-feature-lane/
only exists inside ccam-lanes' own repo, never installed globally, so
/ship-feature-lane is unreachable from its actual intended invocation
context (a session inside some OTHER lane's repo). Shipyard's own
install-claude-assets.sh solves this for its bundled skills the same way.

docs/superpowers/specs/2026-08-05-skills-install-design.md

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+# F3b — `ccam skills install`: making `/ship-feature-lane` actually invokable
+
+**Status:** approved 2026-08-05. Roadmap it belongs to:
+`docs/superpowers/plans/2026-08-03-shipyard-parity-lanes.md` (subsystem **E**, a gap found auditing E1-F3a for Shipyard parity).
+
+## Problem
+
+`.claude/skills/ship-feature-lane/SKILL.md`'s own description says "Invoke inside a lane's working directory" — but Claude Code only auto-discovers a `.claude/skills/` directory when the session's cwd is inside the repo that OWNS that directory. The skill lives only at `ccam-lanes/.claude/skills/ship-feature-lane/SKILL.md`; confirmed empty: `~/.claude/skills/` has no `ship-feature-lane` entry. Every piece built across E1/E2/E3/F1/F3a is unreachable from its actual intended invocation context — a session inside some OTHER lane's repo, not inside ccam-lanes itself.
+
+Shipyard's own `install-claude-assets.sh` solves exactly this: it copies bundled skills into `~/.claude/skills/` (user-level, global) so every project's session sees them.
+
+## Scope
+
+**In scope:**
+- `ccam skills install` — copies `<ccam-lanes repo>/.claude/skills/ship-feature-lane/` to `~/.claude/skills/ship-feature-lane/`, overwriting on reinstall (same "reinstall, not merge" shape as `ccam lanes agents install`).
+- `docs/LANES.md` note.
+
+**Out of scope:**
+- Changing `ccam lanes agents install`'s existing per-lane `.claude/agents/` mechanism. That one's already reachable correctly (Claude Code discovers `.claude/agents/` from the lane's own cwd, which IS where a driving session runs) — this gap is specific to the SKILL, not the agents. No architecture change needed there.
+- Auto-running this from `npm run setup` or any other command. Explicit, like every other install primitive in this codebase (`lanes agents install`, `lanes mcp sync`, `lanes proof-link`) — a human runs it once per machine.
+- Any other bundled skill Shipyard ships (`/review-prs`, `/harness-adapt`) — CCAM has no equivalent of either; out of scope by the same reasoning `pr-reviewer` was dropped (no driving skill to attach to).
+
+## Design
+
+`bin/ccam.js` already has `REPO_ROOT` (`path.resolve(path.dirname(fs.realpathSync(__filename)), "..")`) — the exact self-location primitive Shipyard needed `HARNESS_ROOT` for, already present because `ccam` is npm-linked. No new resolution logic needed.
+
+- `cmdSkillsInstall()` in `bin/ccam.js` (no HTTP round-trip — this has nothing to do with any lane or the dashboard's DB, purely a local file copy from the CLI's own checkout to the user's home directory; matches the existing local-only pattern `cmdLanesProfileInit` already uses via `REPO_ROOT`).
+- Copies `path.join(REPO_ROOT, ".claude", "skills", "ship-feature-lane")` → `path.join(os.homedir(), ".claude", "skills", "ship-feature-lane")` via `fs.cpSync(..., {recursive: true, force: true})` (force: true = overwrite existing files, matching reinstall semantics).
+- Command: `ccam skills install`, no lane argument (nothing lane-specific here).
+
+## Verify
+
+A unit test isn't practical for a command that writes into the real `$HOME` — instead: a manual smoke check (run the command, confirm `~/.claude/skills/ship-feature-lane/SKILL.md` exists and matches the repo's own copy byte-for-byte), same verification shape this repo already uses for routes with no HTTP test harness.