PLN-228: fix: improve install script error handling and diagnostics

[peterulsteen]

Summary

Improves install.sh to cover the full scope of PLN-228. Changes are confined to install.sh; no plugin files touched.

Error surfacing (AC-002, AC-004, AC-005)

• Capture claude CLI stderr to per-run tempfiles under ${TMPDIR:-/tmp}/closedloop-install.XXXXXX and display the underlying error when marketplace registration or plugin install/update fails
• sanitize_stderr strips ANSI color escapes and non-printable control characters using bash ANSI-C quoting ($'\033') plus tr octal ranges so it works under BSD sed (macOS) as well as GNU sed
• Per-run work directory cleaned up via EXIT trap

Idempotent re-run messaging (AC-001, AC-006, AC-007, AC-008, AC-009, AC-010)

• Marketplace pre-check via claude plugin marketplace list --json + jq — re-runs print Marketplace already registered: closedloop-ai instead of re-invoking marketplace add
• Pre/post snapshots via claude plugin list --json + jq classify each plugin as one of three distinct states: Installed: <plugin>, Updated: <plugin> (<old> -> <new>), or Already up to date: <plugin>
• Summary line reports all three counts separately (6 installed, 0 updated, 0 already up to date vs. 0 installed, 0 updated, 6 already up to date), preserving the failed count

Shell guard (AC-011)

• POSIX-portable BASH_VERSION guard at the very top of the script, before any bash-only syntax, so invocations under dash/ash exit cleanly with a single-line guidance message pointing at bash install.sh or the piped-curl invocation
• Also checks BASH_VERSINFO ≥ 3.2 so macOS's default bash still works

jq hard prereq (AC-012)

• jq promoted from soft warn-and-continue to a hard preflight requirement (needed for the snapshot/idempotency logic). Missing jq prints brew install jq / apt install jq and exits before any marketplace or plugin operations run

Test plan

Verified end-to-end on macOS (bash 3.2, BSD sed):

• Fresh install (marketplace and all 6 plugins removed) — all plugins install, 6× Installed: <plugin>, summary All 6 plugins ready (6 installed, 0 updated, 0 already up to date) (AC-001, AC-002, AC-003, AC-007, AC-008)
• Idempotent re-run immediately after fresh install — Marketplace already registered: closedloop-ai, 6× Already up to date: <plugin>, summary All 6 plugins ready (0 installed, 0 updated, 6 already up to date); output visibly different from fresh run (AC-006, AC-007, AC-008, AC-009)
• Simulated marketplace failure (bogus MARKETPLACE_SOURCE) — underlying claude CLI error surfaced to user (Failed to add marketplace: …HTTPS authentication failed…) instead of a generic warn line (AC-005)
• Simulated plugin install+update failure (bogus entry nonexistent-plugin-xyz added to PLUGINS array) — both install and update attempts fail, sanitize_stderr surfaces the real CLI error (Failed to update plugin "nonexistent-plugin-xyz@closedloop-ai": Plugin "nonexistent-plugin-xyz" not found), warn fires, FAILED counter increments, summary shows 3 plugins processed: 0 installed, 0 updated, 2 already up to date, 1 failed (AC-003, AC-004)
• Updated path with a version delta (pre-seeded SNAPSHOT_PRE with a fictitious 0.0.1 for bootstrap) — classification correctly emits Updated: bootstrap (0.0.1 -> 1.2.0), summary shows All 6 plugins ready (0 installed, 1 updated, 5 already up to date) (AC-007 Updated branch, AC-008)
• dash install.sh — bash guard fires, exits 1 with the guidance message, no claude commands executed (AC-011)
• jq hidden from PATH — preflight exits 1 with brew/apt install instructions before any marketplace or plugin operations run (AC-012)

Bugs uncovered and fixed during verification

1. snapshot_version tripped set -e on an empty grep match inside the classification command substitution — fresh installs succeeded but the script errexited before printing any per-plugin status or the summary. Fixed with || true.
2. The UP_TO_DATE branch only incremented the counter with no info line, violating AC-007's per-plugin message requirement. Fixed by emitting Already up to date: <plugin>.
3. sanitize_stderr used GNU-sed-only \x1b / \x00-\x08 escape syntax and errored with RE error: invalid character range on BSD sed (macOS), silently swallowing the CLI errors AC-002/AC-004/AC-005 require to be shown. Rewritten to use a literal ESC via bash ANSI-C quoting plus tr with POSIX octal ranges.

🤖 Generated with Claude Code

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Loop ID: 019d6e91-f371-75eb-84fa-93dfae76959e
Artifact: https://app.closedloop.ai/implementation-plans/PLN-228

[mikeangstadt]

bump build version and it LGTM!