Let the agent use the graph, scene and project commands (#429)

The agent knew 23 of the editor's commands. It could not point a
Variables node at a variable, group nodes, edit ports, transitions,
containers, colliders or the project settings. Stage 5a brings the
catalog to 85 commands in five areas and keeps every answer short.

- The catalog lists names and descriptions only. With a query (an
  area or command names) it adds the arguments. All schemas at once
  would pass the 60 000 character limit of one answer.
- add_port points a Variables node at a variable. The port takes the
  variable's kind, and an unknown name is refused with the list of
  the ones that exist.
- add_group and add_comment take nodes instead of coordinates. They
  follow the nodes after the arrange step, in the same undo step.
- The rule for which list a port picks from moved into portChoices.ts.
  Inspector and agent now share it.
- The frame of a group around nodes moved into annotationDrag.ts, so
  the button and the agent get the same frame.
- list_assets returns the project settings. get_asset shows the
  content of placed containers with the ids overrides need. get_graph
  shows declared ports and frame colors.
- A new node is placed at the height of its port, in the free spot
  whose links cross the fewest others. A source goes left of the node
  it feeds. Before, new nodes always went right of the rest.
- Arrange breaks a tie in crossings by putting the flow on top, and
  exec links pull harder when a column is sorted.
- A comment over a group keeps clear of the group's title bar.
- The agent's instructions and lint_graph ask to look at crossings
  too and to call arrange_graph when there are more than needed.

Left out on purpose: file assets (no upload), paste from the
clipboard, internal wrapper commands and switching plugins on.

Found on the way:
- Variable commands on a Struct asset did not run through
  WithStructTypes. New fields did not reach variables of that type.
- A query "variables" also matched set_variables_scope. A word that
  names an area now means only that area.

Tests:
- agent-catalog (new, 10), agent-edit, graph-arrange (3 new) and
  relay green. 11 bends of the code, all red.
- e2e 71 on atx: 22/22, the new check sees port speed and a group
  around all 4 drawn nodes.
- Live on a test project: a speed variable of 300 moved the player
  to x 150.03 in 0.5 s. A re-placed Variables node landed below Axis
  input with 4 crossings instead of 7.

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

src/editor/agent/tools.json

@@ -27,7 +27,7 @@
   {
     "name": "list_assets",
     "title": "List the assets",
-    "description": "The project's assets with their ids, names and types, and how many objects or nodes each holds. Filter by type and by a part of the name.",
+    "description": "The project's settings (start scene, layers, master bus, ...) and its assets with their ids, names and types, and how many objects or nodes each holds. Filter the assets by type and by a part of the name.",
     "inputSchema": {
       "type": "object",
       "properties": {
@@ -44,7 +44,7 @@
   {
     "name": "get_asset",
     "title": "Read an asset",
-    "description": "One asset as stored: its property values, the rows of its properties (key, kind, default), the objects of a scene or container with their names and positions. A graph is only counted here; read it with get_graph.",
+    "description": "One asset as stored: its property values, the rows of its properties (key, kind, default), the objects of a scene or container with their names and positions (the content of a placed container too, marked fromContainer). A graph is only counted here; read it with get_graph.",
     "inputSchema": {
       "type": "object",
       "properties": { "asset": { "type": "string", "description": "Id of the asset." } },
@@ -56,7 +56,7 @@
   {
     "name": "get_graph",
     "title": "Read a graph",
-    "description": "The graph of a behavior, state machine, shader, particles, sound FX or instrument: each node with its settings and its input and output ports as they are now, the edges between ports, and the groups and notes.",
+    "description": "The graph of a behavior, state machine, shader, particles, sound FX or instrument: each node with its settings and its input and output ports as they are now, the edges between ports, and the groups and comments (notes). A node that declares its own ports lists them under ports.",
     "inputSchema": {
       "type": "object",
       "properties": { "asset": { "type": "string", "description": "Id of the asset holding the graph." } },
@@ -68,7 +68,7 @@
   {
     "name": "lint_graph",
     "title": "Check how a graph reads",
-    "description": "Counts what makes a graph hard to read, as the user sees it: nodes on top of each other (overlaps), links that cross (crossings), links running over a node that is not theirs (throughNodes), links running right to left (backwards), and the longest links, with a few ids of each. Aim for 0 overlaps and 0 throughNodes. To mend: the command arrange_graph, or a second Get or Owner node next to a far-off user instead of one long link.",
+    "description": "Counts what makes a graph hard to read, as the user sees it: nodes on top of each other (overlaps), links that cross (crossings), links running over a node that is not theirs (throughNodes), links running right to left (backwards), and the longest links, with a few ids of each. Aim for 0 overlaps, 0 throughNodes and 0 backwards, and for no more crossings than the links need: two links leaving one node far apart, like exec and dt, cross what comes in between them. To mend: the command arrange_graph, or a second Get or Owner node next to a far-off user instead of one long link.",
     "inputSchema": {
       "type": "object",
       "properties": { "asset": { "type": "string", "description": "Id of the asset holding the graph." } },
@@ -80,7 +80,7 @@
   {
     "name": "catalog",
     "title": "What can be made",
-    "description": "Looks things up before an edit. topic \"commands\": every command run_commands knows, with its arguments. topic \"nodes\" with asset: the nodes that graph can hold; with query, the best matches in full (ports, settings). topic \"asset_types\": the kinds of asset; with type, that kind's properties. topic \"variable_kinds\": what a variable can hold.",
+    "description": "Looks things up before an edit. topic \"commands\": the commands run_commands knows by area, each with what it does; with query (an area, or command names), those commands with their arguments. topic \"nodes\" with asset: the nodes that graph can hold; with query, the best matches in full (ports, settings). topic \"asset_types\": the kinds of asset; with type, that kind's properties. topic \"variable_kinds\": what a variable can hold.",
     "inputSchema": {
       "type": "object",
       "properties": {
@@ -88,7 +88,7 @@
         "asset": { "type": "string", "description": "For nodes: id of the graph asset." },
         "query": {
           "type": "string",
-          "description": "For nodes: words to search for, like \"key held\" or \"move\"."
+          "description": "For nodes: words to search for, like \"key held\" or \"move\". For commands: an area or command names, like \"graphs\" or \"add_port add_group\"."
         },
         "type": { "type": "string", "description": "For asset_types: one type to describe in full." }
       },