Add preflight-tests step to mol-polecat-work

Checks tests on main BEFORE starting work. Scotty Principle:
- Quick fix (<15 min): Fix it, commit, continue
- Big fix: File bead, notify Witness, proceed

Closes gt-3zkjw

.beads/formulas/mol-polecat-work.formula.toml

@@ -33,7 +33,7 @@ You are an autonomous worker. You:
 | Context filling | Use gt handoff to cycle to fresh session |
 | Unsure what to do | Mail Witness, don't guess |"""
 formula = "mol-polecat-work"
-version = 2
+version = 3
 
 [[steps]]
 id = "load-context"
@@ -131,10 +131,81 @@ If rebase conflicts:
 
 **Exit criteria:** You're on a clean feature branch, rebased on latest main."""
 
+[[steps]]
+id = "preflight-tests"
+title = "Verify tests pass on main"
+needs = ["branch-setup"]
+description = """
+Check if the codebase is healthy BEFORE starting your work.
+
+**The Scotty Principle:** Don't walk past a broken warp core. But also don't
+let someone else's mess consume your entire mission.
+
+**1. Check tests on main:**
+```bash
+git stash                   # Save your branch state
+git checkout origin/main
+go test ./...               # Or appropriate test command
+```
+
+**2. If tests PASS:**
+```bash
+git checkout -              # Back to your branch
+git stash pop               # Restore state
+```
+Continue to implement step.
+
+**3. If tests FAIL on main:**
+
+Make a judgment call:
+
+| Situation | Action |
+|-----------|--------|
+| Quick fix (<15 min) | Fix it, commit to main, then continue |
+| Medium fix (15-60 min) | Fix if it blocks your work, else file bead |
+| Big fix (>1 hour) | File bead, notify Witness, proceed with your work |
+
+**Quick fix path:**
+```bash
+# Fix the issue
+git add <files>
+git commit -m "fix: <description> (pre-existing failure)"
+git push origin main
+git checkout -
+git stash pop
+git rebase origin/main      # Get your fix
+```
+
+**File and proceed path:**
+```bash
+bd create --title "Pre-existing test failure: <description>" \
+  --type bug --priority 1
+
+gt mail send <rig>/witness -s "NOTICE: Main has failing tests" \
+  -m "Found pre-existing test failures on main.
+Filed: <bead-id>
+Proceeding with my assigned work ({{issue}})."
+
+git checkout -
+git stash pop
+```
+
+**Context consideration:**
+If fixing pre-existing failures consumed significant context:
+```bash
+gt handoff -s "Fixed pre-existing failures, ready for assigned work" \
+  -m "Issue: {{issue}}
+Fixed: <what you fixed>
+Ready to start: implement step"
+```
+Fresh session continues from implement.
+
+**Exit criteria:** Tests pass on main (or issue filed), ready to implement."""
+
 [[steps]]
 id = "implement"
 title = "Implement the solution"
-needs = ["branch-setup"]
+needs = ["preflight-tests"]
 description = """
 Do the actual implementation work.