Observability for Harper binary resolution + loopback setup verification

[heskew]

The uncontroversial half of #23 — no resolution-order or dependency changes, just making the two silent failure modes visible:

Binary resolution logging

getHarperScript now logs the resolved Harper path and which rule chose it (harperBinPath option / HARPER_INTEGRATION_TEST_INSTALL_SCRIPT / node_modules / ancestor dist), once per distinct path. When the node_modules copy wins while ./dist/bin/harper.js also exists, it warns with the env-var override — the exact situation in #23 where the harness silently tested the published npm package instead of the local build.

Loopback setup verification

setup-loopback.sh previously printed its ✓ success line unconditionally — a partial run (expired sudo credential mid-loop, interruption) claimed success and left the test runner failing later on missing addresses with no connection back to the setup step. The script now re-checks every address after the loop and, on any miss, prints the exact per-address fix commands and exits non-zero. It also announces the range up front, which doubles as a tell when two checkouts run different package versions with different pool conventions (0.3.x started at .1, current starts at .2).

Verification

• npm run check clean, npm test 19/19 passing
• bash -n clean on the script; verification loop exercised manually on macOS (missing-alias case prints the fix command and exits 1; complete case prints ✓)

Deliberately not included (pending direction on #23): peerDependenciesMeta.harper.optional or any resolution-precedence change.

🤖 Generated with Claude Code

https://claude.ai/code/session_01RXx78W5LxbvxEdSyrB1vvn

[gemini-code-assist]

Code Review

This pull request introduces robust verification for loopback address configuration in setup-loopback.sh and adds detailed logging and warnings for Harper binary resolution in harperLifecycle.ts to prevent testing stale builds. The review feedback suggests optimizing the loopback verification script by caching the ifconfig output to avoid spawning subprocesses in a loop, and improving the local build warning robustness by walking up the directory tree instead of relying solely on process.cwd().

[kriszyp]

The success check can still accept the configuration this script is meant to repair. If an old 127.0.0.$i alias has a /8 netmask and either the delete or re-add fails (those statuses are currently ignored), the old alias remains in LO0_STATE; this IP-only grep passes and prints ✓ even though the overlapping-subnet/mDNS CPU problem remains. Could the verifier require the matching alias to have netmask 0xffffffff (macOS's representation of /32) before reporting success? Checking/reporting a failed add would also make the immediate error clearer. A fake-ifconfig regression test with an existing /8 alias would lock this down.