feat(std): fill the by-chance vocabulary gaps — Const, Div, Abs, Max, Min

Five new rostered node types (count-pin 23 -> 28, both the in-crate
shape test and the cross-boundary CLI vocabulary e2e): Const is unary
with an f64 'value' param — the clock input drives it, its value is
ignored, since a zero-input node never evaluates in the total-push
engine — mirroring EqConst's constant-as-param pattern; Div is binary
IEEE-754 (x/0 -> signed inf, 0/0 -> NaN, unit-tested, no error
channel); Abs unary mirroring Sqrt; Max/Min binary pairwise, distinct
from the windowed RollingMax/RollingMin.

Acceptance proof: the committed executable spec composes an RSI-class
gain/loss-split-and-ratio signal purely from blueprint data through
std_vocabulary and runs it to hand-computed RS values — the r_meanrev
constant-folding workaround is no longer forced.

Verified: headline test green, aura-std 163/0, full workspace suite
green (independent mini-verify), clippy -D warnings clean.

closes #236

crates/aura-cli/tests/graph_construct.rs

@@ -121,8 +121,8 @@ fn graph_introspect_vocabulary_lists_exactly_the_closed_roster_count() {
     let lines: Vec<&str> = stdout.lines().filter(|l| !l.is_empty()).collect();
     assert_eq!(
         lines.len(),
-        23,
-        "the std-only (no project) vocabulary has exactly the roster's 23 entries: {stdout}"
+        28,
+        "the std-only (no project) vocabulary has exactly the roster's 28 entries: {stdout}"
     );
 }