Add theorem prover docs page with Phase 2 constraint solving

- prove.sx Phase 2: bounded model checking with 34 algebraic properties
  (commutativity, associativity, distributivity, inverses, bounds, transitivity)
- prove.sx generates SMT-LIB for unbounded Z3 verification via z3-expr
- New docs page /plans/theorem-prover with live results (91/91 sat, 34/34 verified)
- Page helper runs both proof phases and returns structured data
- Parser: re-add ' quote syntax (removed by prior edit)
- Load prove.sx alongside z3.sx at startup

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

sx/sxc/pages/docs.sx

@@ -626,10 +626,14 @@
     :sub-nav (~section-nav :items plans-nav-items
                :current (find-current plans-nav-items slug))
     :selected (or (find-current plans-nav-items slug) ""))
+  :data (case slug
+    "theorem-prover" (prove-data)
+    :else nil)
   :content (case slug
     "status" (~plan-status-content)
     "reader-macros" (~plan-reader-macros-content)
     "reader-macro-demo" (~plan-reader-macro-demo-content)
+    "theorem-prover" (~plan-theorem-prover-content)
     "sx-activity" (~plan-sx-activity-content)
     "predictive-prefetch" (~plan-predictive-prefetch-content)
     "content-addressed-components" (~plan-content-addressed-components-content)