Loki Mode v7.41.2

CI integrity patch. The v7.41.1 release shipped to npm but its Tests workflow
went red on two test-only defects (the runtime code was unaffected). This patch
makes the suite green again and adds a permanent guard for the class of
regression that v7.41.1 introduced.

Fixed

• Shell tests: tests/test-completion-summary.sh now accepts the v7.41.1
  pathspec-filtered review_cmd (git diff <sha>..HEAD -- . ':(exclude).loki/');
  the glob previously required the command to end at ..HEAD.
• ShellCheck: _loki_caveman_infer_level in autonomy/lib/claude-flags.sh is
  annotated # shellcheck disable=SC2120 (its $1 is intentionally optional with
  a global fallback). Older shellcheck on CI flagged SC2120 as a warning and
  failed the lint gate; newer shellcheck does not.

Added

• tests/test-plan-json-smoke.sh: a fast direct regression guard asserting
  loki plan --json exits 0, emits valid JSON with a populated
  cost.iterations_by_model, and never prints "unbound variable" (the v7.41.1
  heredoc $5-unbound regression). Wired into tests/run-all-tests.sh.