paper v4.2: visual PDF inspection pass — fix broken hyphenation minima

Read all 18 rendered pages with own eyes (per author order: never trust
tex->pdf as a given). Found: this portable TeX install's format ships a
broken righthyphenmin (verified: \showhyphens{its} -> 'it-s'), which
produced 'a receipt for a leaf is it-/s index' on p.7. Fixed globally
(\lefthyphenmin=2 \righthyphenmin=3); document-wide rescan shows zero
short-tail breaks. Everything else verified as intended: title block,
narrowed abstract, T1-T4 with x=0 note, Def 1, G1-G3, honest-width 4.4,
ConsRec display, frontier Lemma 2, Thm 2/3, claim matrix (auto-numbered
Table 1, refs consistent), exact 8|4 Figure 1, forks Table 2 caption,
acknowledgments both assistants, all 20 refs w/ pages, App A verbatim
values, App B code block, App C boundary order, App D namespace note.

18 pages, 106 tests green, accumulator untouched.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

paper/ltl.tex

@@ -16,6 +16,8 @@
 \usepackage{booktabs}
 \usepackage{lmodern}
 \usepackage{microtype}
+% this TeX install's format ships righthyphenmin=1 ('it-s'); restore standard
+\lefthyphenmin=2 \righthyphenmin=3
 \usepackage{tikz}
 \usetikzlibrary{fit,positioning,decorations.pathreplacing}