fix(assets): address PR #98 review — all 7 items

Warning fix:
- Remove torso_upper from hides in 3 coverage.json files
  (coveralls_basic, jacket_utility, shirt_henley) and the generator
  script — redundant when torso_variant is "full"

Suggestions addressed:
- Add pants_cargo authoring note about foot segment distinction
- Add pipeline_log.json provenance output to Surface Deform batch
  pipeline (tracks method per variant: surface_deform/shrinkwrap/copy)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

client/assets/characters/clothing/coveralls_basic/coverage.json

@@ -1,7 +1,6 @@
 {
   "hides": [
     "torso",
-    "torso_upper",
     "arm_upper_l",
     "arm_upper_r",
     "arm_lower_l",

client/assets/characters/clothing/jacket_utility/coverage.json

@@ -1,7 +1,6 @@
 {
   "hides": [
     "torso",
-    "torso_upper",
     "arm_upper_l",
     "arm_upper_r",
     "arm_lower_l",

client/assets/characters/clothing/shirt_henley/coverage.json

@@ -1,7 +1,6 @@
 {
   "hides": [
     "torso",
-    "torso_upper",
     "arm_upper_l",
     "arm_upper_r"
   ],