Move the FX placeholder seeder into tools/

_seed_placeholders.gd is a one-off generator, not a shipped effect — it belongs
with the other headless tooling (bake_crowd_sheet, preview_*), not in the fx/
runtime dir Siim edits. Rename it to tools/seed_fx_placeholders.gd (matching the
dir's verb_noun convention) and repoint the two doc-comment references.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Pq1VX2o1ZfiNRdCjD294wf

fx/fx.gd

@@ -4,7 +4,7 @@ extends Node
 ## Autoload singleton. Usage:  Fx.spawn(&"blood_burst", hit_transform)
 ##
 ## Scenes are loaded lazily (not preloaded) so this autoload compiles and boots even before the
-## placeholder .tscn are seeded — see fx/_seed_placeholders.gd.
+## placeholder .tscn are seeded — see tools/seed_fx_placeholders.gd.
 
 const _PATHS: Dictionary = {
 	&"blood_burst": "res://fx/blood_burst.tscn",

tools/seed_fx_placeholders.gd

@@ -2,7 +2,7 @@ extends SceneTree
 ## Seeds the placeholder effect .tscn (and the gallery scene) once, headless. Those .tscn are the
 ## source of truth Siim edits in the inspector — this script only builds their first-draft defaults
 ## (ported from the old code-built particles). Re-run only to reset a placeholder from scratch:
-##   godot --headless --script fx/_seed_placeholders.gd
+##   godot --headless --script tools/seed_fx_placeholders.gd
 
 const _EFFECT_SCRIPT := "res://fx/one_shot_effect.gd"
 const _GALLERY_SCRIPT := "res://fx/effect_gallery.gd"