health scores a crashing tsc as CLEAN because EXIT_CODE reads tail's status

\`health/SKILL.md.tmpl\` line 125 runs \`tsc --noEmit 2>&1 | tail -50\` and line 126 sets \`EXIT_CODE=$?\`. Without \`pipefail\`, \`$?\` is tail's status, which is 0 whenever tail ran.

Input that passes while broken: tsc that fails before emitting diagnostics (missing \`typescript\`, a broken \`tsconfig.json\`, an out-of-memory crash, a non-zero exit with a bare stack trace). No \`error TS\` lines survive, \`EXIT_CODE\` is 0, and the scoring rule (count \`error TS\` lines) awards 10/10 CLEAN to a typecheck that never ran.

Fix: prefix the block with \`set -o pipefail\`, or capture \`EXIT_CODE=${PIPESTATUS[0]}\` immediately after the pipeline.

Start in health/SKILL.md.tmpl at lines 125-126 and review how the tsc pipeline determines EXIT_CODE. Run the health check with a failing TypeScript setup such as a missing compiler or broken tsconfig.json, then confirm that the result is no longer scored CLEAN and that successful checks still pass.

Written by the indexing model from the issue text.