ah-nyl.16 fix: wiring review findings 1-7 (flag swallowing, agenthubd tests, polish) Past Stand

Hostile review of the wiring commits (e116576/ae38c10/254c0f8) returned FIX-FIRST. Fix ALL seven. Line refs @ HEAD.

W1 BLOCKER (cmd/agenthubd/main.go:70, cmd/ahub/main.go:105,200): stdlib flag.Parse stops at the first positional and nothing checks fs.NArg() -> `agenthubd serve --config ./missing.yaml` silently starts with ./agenthub.yaml defaults (exit 0, WRONG config); `ahub status 127.0.0.1:9188` silently queries the default :9100 (wrong daemon, exit 0). FIX: after each fs.Parse (three call sites), reject fs.NArg() > 0 with a usage error to stderr and exit 2. Tests for all three sites.

W2 BLOCKER-adjacent (cmd/agenthubd): zero tests despite run() being injection-shaped. ADD minimum: bad flag -> exit 2; positional arg -> exit 2 (W1); missing/broken config -> exit 1; invalid --log-level -> exit 2; connection-refused preflight -> exit 1 AND stderr contains the operator-friendly preflight message. Use the injected args/stderr seams; httptest fake vikunja where needed (views endpoint refusing/absent). Keep each test <2s.

W3 LOW (cmd/ahub/main.go:219-230 + internal/config/config.go:422-427): single-problem validate-config prints the path twice and skips the bullet format (culpa.Join(1) returns the bare error so the multi-unwrap loop never fires); also the existing two-problem test passes via Contains even if the multi-unwrap loop is deleted. FIX in ahub only (do not change config's wrap): fallback branch prints the problem without the duplicated prefix; pin the EXACT multi-line output format for the >=2 case and the exact single-line format for the ==1 case with require.Equal.

W4 LOW (internal/httpapi/httpapi.go:116-119): wire http.Server.ErrorLog = slog.NewLogLogger(<handler>, slog.LevelError) so per-connection panics/header noise join the structured stream instead of log.Default() raw text. Test optional (constructor wiring assertion is enough).

W5 INFO (cmd/agenthubd/main.go:184): the explicit stop() next to defer stop() is load-bearing — it unregisters signal handling so a second SIGTERM during the drain hard-kills (desired escape hatch). Add the pinning comment so a cleanup doesn't remove it.

W6 INFO (internal/httpapi run-exit): trailing garbage after the JSON object is accepted (Decode reads one value). Add a dec.More() strictness check -> 400 on trailing content; adjust/add test.

W7 INFO (cmd/agenthubd/main.go:117): SIGTERM during the preflight window logs the scary "startup preflight failed ... check vikunja.url" message and exits 1. Branch on errors.Is(err, context.Canceled) -> quiet "shutdown requested during startup" log, still exit 1 (or 0 — pick 1 for "did not reach ready", document in the message). Test if cheap via the run() seam.

Constraints: scope = cmd/agenthubd/, cmd/ahub/, internal/httpapi/. A sibling agent is writing e2e/ concurrently — do NOT touch e2e/, internal/<anything else>, docs/, .beads/, go.mod. Conventions: testify, culpa, slog. Build/vet/test -race ONLY your three packages; never ./... . Commits: 'cmd: reject positional args, add agenthubd run() tests' + 'httpapi: strict run-exit decode, slog ErrorLog' (split as sensible); hooks bypassed (git -c core.hooksPath=/tmp/nohooks commit); retry on index.lock; no push.