Seven localized source corrections found during translation QA

Hello — while checking complete translation targets against the English source, I found seven small, high-confidence source defects. I verified each against current master at 1e960beff9ed7835bf3e3f1335e21af3439cd107 as well as the frozen translation authority 9620cc7.

This list deliberately excludes everything already raised in #432, #433, or the findings ledger linked from #432.

1. content/proof-theory/proof-search/tableaux.tex:29
shows that would show that → would show that (or simply shows that).

2. content/second-order-logic/metatheory/second-order-arithmetic.tex:41–42
\Domain{M})$. → \Domain{M}$). The parenthesis belongs to the surrounding “i.e.” clause, not inside the formula.

3. content/second-order-logic/metatheory/undecidability-and-axiomatizability.tex:33
$\Sat{M}{!P \lif !A$}. → $\Sat{M}{!P \lif !A}$. This closes the second argument of \Sat before math mode ends.

4. content/set-theory/ord-arithmetic/using-addition.tex:61
   Insert the missing =: $\setrank{A \times B} = \max(\setrank{A}, \setrank{B}) \ordplus 2$.

5. content/first-order-logic/tableaux/provability-consistency.tex:122
On the left left side → On the left side.

6. content/sets-functions-relations/size-of-sets/non-enumerability-alt.tex:135
iff if → iff.

7. content/proof-theory/sequent-calculus/invertibility.tex:331,366,372
   At line 331, \RightR{\lexists} → \RightR{\lforall}, since the displayed principal formula is universal. At lines 366 and 372, !B → !B(t), matching the existential-rule premise at line 360.

These are source-quality notes for maintainer review; no upstream endorsement of any translation is implied.

Start by reviewing the seven cited .tex files and line ranges against master commit 1e960beff9ed7835bf3e3f1335e21af3439cd107 and translation authority 9620cc7. Check each listed wording, punctuation, formula, and notation correction, while confirming the findings are not covered by #432, #433, or its ledger. Done means all seven source-quality findings have been reviewed and addressed or dispositioned by the maintainer.