feat(cli): 0.R4 - ludic deps sees through fn values (widest_reach) and lists the widest functions (--widest N, --reach N)

A step list or a registry of fn values takes no state and still reaches every state its steps take.
The compiler now writes `reach <n> <function>` - every state a function can come to by a call, a
`fn f` it writes or a global holding fn values it reads, to a fixed point - and ludic deps reports
widest_reach beside widest_function, with how many of those states the function does not take
(Maroon Lake: app_boot, 72, all 72 through fn values). --widest N lists the N functions that take the
most states with what each reaches; --reach N orders them by reach. A baseline without widest_reach
does not hold it until rewritten.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

examples/state/reach.ludic

@@ -0,0 +1,21 @@
+# ludic deps --reach: a step list takes no state and still reaches every state its steps take
+program Reach {
+  state Alpha { n: int = 0 }
+  state Beta { n: int = 0 }
+  state Gamma { n: int = 0 }
+  function step_a(a: mut Alpha) -> void { a.n += 1 }
+  function step_b(b: mut Beta) -> void { b.n += 2 }
+  function step_c(c: mut Gamma) -> void { c.n += 3 }
+  let STEPS: []fn() -> void = [fn step_a, fn step_b]
+  function run_steps() -> void {
+    for i in 0 .. len(STEPS) { STEPS[i]() }
+  }
+  function one(c: mut Gamma) -> void {
+    step_c(c)
+    run_steps()
+  }
+  entry (c: mut Gamma) {
+    one(c)
+    print(`{c.n}`)
+  }
+}