Describe the event order and the Order field (#264)

- Behaviors: new section Event order. A frame runs event kind by
  event kind, Order sorts within a kind, ties go by hierarchy and
  then creation order. The lifecycle sentence on destroying is fixed.
- Architecture: names core/graph/eventOrder.ts.
- Development: the e2e total is 1551, measured.

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

Architecture.md

@@ -81,6 +81,7 @@ src/core/graph/        graph model, NodeRegistry/NodeContext/values (a travellin
                        narrows one down to what a PropertyBag may hold, #157), interpreter, dropTarget, nested (behaviors as nodes),
                        emitGraph (the walk both graph compilers share: each node once, in dependency order; cycles and property names reported),
                        sharedState (what a run shares: a bag per Variables asset, the state of a global machine; what a scene change carries forward and what it starts afresh, #164),
+                       eventOrder (#264: the Order setting of event nodes and how the pulses of one event kind are sorted),
                        portTypes (#207: ports of one node that carry the same value, and the type their inputs agree on),
                        savedValues (#166: the SaveArea a run reads persistent Variables assets from and writes them to, and restoring a save through today's declaration),
                        stateMachine (the State node, a machine's states, the ports they become), variablePorts, propertyPorts,

Behaviors.md

@@ -516,9 +516,20 @@ playing use the same two words.
   states survive, and switching it on again is `On enable`, not `On start`. `On destroy` runs when
   the object leaves the world — through `Destroy`, as a child of a destroyed object, and when the
   game stops or restarts; a restart is therefore `On disable` → `On destroy` → (new world) `On start`
-  → `On enable`. The frame that destroys an object still runs to its end, the two farewell events
-  follow at the end of it; an object destroyed while off gets `On destroy` alone. Off and on again
-  within one frame is no edge: neither event fires.
+  → `On enable`. An object destroyed during a frame gets no further events of that frame, the two
+  farewell events follow at the end of it; an object destroyed while off gets `On destroy` alone.
+  Off and on again within one frame is no edge: neither event fires.
+- **Event order**: a frame goes event kind by event kind, each across every behavior: `On disable`,
+  `On enable`, `On key down`, `On key up`, `On key held`, `On timer`, `On collision enter`,
+  `On collision stay`, `On collision exit`, `On animation finished`, `On click`, `On mouse wheel`
+  and last `On update`. So a key event of any behavior runs before the first `On update`. The state
+  events a kind caused follow right after it. New instances get all their `On start` and then all
+  their `On enable`, a finished world all `On disable` and then all `On destroy`. Within one kind
+  every event node has the setting *Order*, a whole number, 0 by default: a lower order runs first,
+  whatever behavior it sits in, so `-10` runs before everything left at 0. Equal orders run in
+  hierarchy order, top to bottom as the hierarchy shows it right now (a spawned object stands where
+  it was put), and within one graph in the order the nodes were made. The node shows `Order: 5`
+  only when the order is not 0.
 - **Runtime**: `BehaviorSystem` creates one `GraphInterpreter` per behavior entity; graphs only
   touch world entities. A runaway pulse throws (see *Loops* for the two limits) and stops play
   with a notice.

Development.md

@@ -15,7 +15,7 @@ npm run build        # writes dist/ and regenerates index.html
 php tools/make-user.php <name> <password> [admin|user]        # an account; every tool signs in (see Accounts)
 php tests/php/accounts.test.php                               # the API's account rules, no server needed (CI's gate job)
 php tests/php/snapshots.test.php                              # the snapshot store (#231), the same way
-node tools/seed-e2e.mjs && node tools/e2e.mjs                 # 1549 editor checks, screenshots in /tmp/gm-e2e-*.png
+node tools/seed-e2e.mjs && node tools/e2e.mjs                 # 1551 editor checks, screenshots in /tmp/gm-e2e-*.png
 GM_STEPS=20 node tools/e2e.mjs                                # or 1-12, or 6,20 — a subset while working on one step
 ./e2e.sh start [GM_STEPS]                                     # the same run detached, see below
 ./e2e.sh status                                               # live progress, or the last run's result