Consolidate duplicated editor code, trim comments, refresh README

Split GraphCanvas (1076 -> 831 lines) into EdgeLayer and graphMenus;
the port and marker menus were the same list and are now one function.
Value specs of the inspector and the list tab share valueSpecs.ts, and
the remaining copies (compound commands, type glyphs, typed asset
lookup, name rule, play/editor world setup, marquee) are merged.

Four copies had already drifted apart; merging them fixes:
- "Disconnect N links" in the port menu is one undo step, not N
- "+ Add collider" is hidden on a placed container instance, as in
  the hierarchy menu, instead of always failing
- a bool property coerced from the text "false" becomes false
- a port command on an unknown node type reports instead of crashing

Comment-only edits leave the bundle byte-identical. README corrected in
35 places (step limit, jump-run clock, suite duration, 409 body, ...).

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

src/core/graph/nested.ts

@@ -1,4 +1,5 @@
 import { textOf } from '../model/Properties';
+import { isValidFieldName } from '../properties/PropertySchema';
 import { type DeclaredPort, declaredPortType, type Graph, type GraphNode } from './Graph';
 import type { BehaviorLookup } from './lookup';
 import { nodeDef, type NodeDef, type PortDef } from './NodeRegistry';
@@ -22,7 +23,7 @@ export function declaresVariablePorts(type: string): boolean {
 
 /** Identifier-like, and not `exec`: that key belongs to the fixed flow port of every terminal node. */
 export function isValidPortName(name: string): boolean {
-  return /^[A-Za-z_][A-Za-z0-9_]*$/.test(name) && name !== 'exec';
+  return isValidFieldName(name) && name !== 'exec';
 }
 
 /** The single start (or end) node of a graph; a second one is ignored. */