P3 review: the surface, docs and proofs

Split kernel::entry_flows into entry_movements and flows_of so the
reversal-mirror proof fits CI; prove runs the fast harnesses, prove-slow
the 8 slow ones (own job in scheduled CI), prove-all both. Laws in
verification.md renumbered 1-31 with a table of all 55 harnesses.

MCP docs checked against the 115 tools (about 60 fixes) with a test that
every tool is documented; rules.md cross-references fixed; bookspec
statuses and loader tightened; viewer notes wrap and accounts sort by
code; STATUS.md says P3 is built, cutover pending.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T3gXMVt7XJPi6ens1or9Dj

crates/ledger-core/src/kernel.rs

@@ -680,7 +680,17 @@ pub fn apply_cash<T: Amount>(cash: T, movements: &[T], applied: &mut [T]) -> Opt
 /// operating, investing, financing, each up to its own movement; what is
 /// left of a section's movement is the part no cash settled. `None` when
 /// the lines don't net to zero (never for a posted entry) or on overflow.
+/// It is [`entry_movements`] then [`flows_of`], so each is proved on its
+/// own (docs/verification.md, law 10).
 pub fn entry_flows<T: Amount>(lines: &[(Flow, Side, T)]) -> Option<EntryFlows<T>> {
+    let (cash, moved) = entry_movements(lines)?;
+    flows_of(cash, moved)
+}
+
+/// An entry's net movement on its cash lines and on each section's,
+/// `(cash, [operating, investing, financing])`, debit-positive. `None`
+/// on overflow.
+pub fn entry_movements<T: Amount>(lines: &[(Flow, Side, T)]) -> Option<(T, [T; 3])> {
     let mut cash = T::ZERO;
     let mut moved = [T::ZERO; 3];
     for &(flow, side, amount) in lines {
@@ -693,6 +703,13 @@ pub fn entry_flows<T: Amount>(lines: &[(Flow, Side, T)]) -> Option<EntryFlows<T>
         };
         *slot = slot.checked_add(delta)?;
     }
+    Some((cash, moved))
+}
+
+/// The cash flows of an entry whose cash lines moved `cash` and whose
+/// sections moved `moved` ([`entry_flows`]). `None` when they don't net
+/// to zero, or on overflow.
+pub fn flows_of<T: Amount>(cash: T, moved: [T; 3]) -> Option<EntryFlows<T>> {
     // Balanced lines only: every part below rests on it.
     let mut total = cash;
     for &m in &moved {