refactor(install): S1 — framework-only install.sh (one-click-installer Stage 1)

[artyhoo]

Summary

Stage S1 of the one-click-installer umbrella (plan: docs/superpowers/plans/2026-05-31-one-click-installer.md Task 1, merged #441). Reduces install.sh to framework-only: the three companion-install blocks (Superpowers / TaskMaster / OhMyOpencode) and the --companions arg machinery move out — companion selection migrates to the upcoming ./setup manifest (S2/S3).

Changes

• install.sh −128 LOC: deleted section 3.5 «Optional companion installs» in full (header comment → closing fi, incl. the non-interactive COMPANIONS=none fallback) + COMPANIONS init/arg-parse. The # ── aif-handoff integration note block survives intact (framework skill-context, not a companion install).
• New TDD test tests/install-sh/no-companion-blocks.test.sh (verbatim from plan Task 1 Step 1): 4 assertions that install.sh carries no companion-install logic. Red-phase verified before trim (PASS=0 FAIL=4), green after (PASS=4 FAIL=0).

Prior-art consult

• No capability commit in this PR — pure removal + test for existing surface (refactor(install) commit; no new dep, no new ≥50/80-LOC module under packages/). Prior-art for the umbrella's capability stages lives in spec §10/§11 (aif-handoff installMcpServer precedent) and lands with S2+.
• No new capability area surfaced.
• No SSOT entries matched (removal-only change).
• context7 N/A — no new capability area.

Test plan

• bash tests/install-sh/no-companion-blocks.test.sh → PASS=4 FAIL=0 (worker verify-trace, red→green TDD cycle evidenced)
• bash -n install.sh → exit 0 (worker verify-trace)
• Manual smoke: install.sh ts-server --dry-run in throwaway dir, non-interactive (</dev/null) → exit 0, «✅ Dry-run complete. Nothing was written.», zero companion prompts (grep on full output: companion|superpowers|taskmaster|ohmyopencode|[y/N] → 0 matches)
• Regression guard: sibling tests/install-sh/transform-internal-refs.test.sh → 7 pass / 0 fail
• grep -ni 'companion\|COMPANIONS' install.sh → zero matches; paid-by-default sweep (T-OCI-B): no surviving auto-install path of any companion (remaining claude plugin-shaped strings are echo-only next-steps prose)
• CI ci-success gate on this PR (pending — runs on PR)

§1.7 Self-discipline check (REQUIRED if PR touches discipline-bearing files)

§1.7 Skipped: refactor-only trim of install.sh + paired TDD test; no discipline-bearing surface (rules/principles/templates) touched.

🟢 Простыми словами

install.sh теперь ставит только сам фреймворк и больше не предлагает установить компаньоны (Superpowers и др.) — этим займётся единая команда ./setup, которую добавят следующие стадии. Поведение зафиксировано тестом из 4 проверок.

Observations (out of scope, per CLAUDE.md PR strategy)

• Plan Task 1 Step 5 expects «Dry-run complete» within tail -5, but install.sh prints the next-steps block AFTER that marker (pre-existing output order; marker at line 55/77 of the dry-run log). Plan expectation imprecise even before the trim — informational only.
• Plan's absolute line anchors (:340-455, :457, :60/:62) drifted 2-7 lines vs current install.sh; executed by content-anchoring. Notably the deletion had to start at the # ─── 3.5 … header comment (:333), not the echo line the plan names — else the test's own assertion 4 stays red.