fix(inplace,embed): input set back mid-flight, report inputs, ambiguous anchors

Four items owed after S5b, reported by design-dev during the anti-slop run:

- carry() measured a sent-then-changed form against its OLD DEFAULTS. An
  answer set back mid-flight to the value the page first showed read as
  untouched, and the swap put the just-saved value over it. A form sent and
  then changed is now measured against its sent snapshot (sentSet.snapOf).
- The embed's clean-batch reload saw only our own forms. A report's own
  inputs lost whatever the operator had typed into them. Unsaved text in
  any control we don't own now holds the reload, and the page says so.
- Two r2b.toml rows ("D3 a stored theme...", "D3 forced light...") matched
  twice, so they proved only by where the first match fell. Both are
  re-anchored, and scripts/mutation_check.py now refuses any anchor that
  matches more than once. A new tool control covers that.
- The r2_flow contract's C3 steps 2 and 4 now say what S5b superseded. U3
  gains the report-input rule.

Mutation rows: u3_submit_all +1, r2_submit_all +1. Four rows were
re-anchored onto the moved lines.

tests/mutations/r2_submit_all.toml

@@ -96,15 +96,24 @@ label = "a sent form counts as sent even when it changed after the press"
 file = "booth/templates/base.html"
 test = "tests/test_flow_browser.py::test_a_change_to_a_sent_pick_during_the_flight_is_kept"
 old = '''
-          if (recs[i].key === k && recs[i].snap === serial(f)) return true;'''
+        return snap !== null && snap === serial(f);'''
 new = '''
-          if (recs[i].key === k) return true;'''
+        return snap !== null;'''
 
 [[mutation]]
 label = "no form counts as sent (a saved note's text carries back as a draft)"
 file = "booth/templates/base.html"
 test = "tests/test_flow_browser.py::test_a_saved_notes_box_comes_back_empty"
 old = '''
-          if (recs[i].key === k && recs[i].snap === serial(f)) return true;'''
+          if (recs[i].key === k) return recs[i].snap;'''
 new = '''
-          if (false) return true;'''
+          if (false) return recs[i].snap;'''
+
+[[mutation]]
+label = "a sent-then-changed form is measured against its OLD defaults (a value set back mid-flight is lost)"
+file = "booth/templates/base.html"
+test = "tests/test_flow_browser.py::test_a_sent_pick_set_back_to_its_first_value_mid_flight_is_kept"
+old = '''
+        var snap = isSent.snapOf ? isSent.snapOf(el.form) : null;'''
+new = '''
+        var snap = null;'''