Align preview tool layout to Palette Manager base and add last generated preview display - PR_26126_004-preview-tool-layout-refinement

Author: DavidQ

docs/dev/codex_commands.md

@@ -1,19 +1,19 @@
-# Codex Commands - PR_26126_003-preview-tool-layout-spec
+# Codex Commands - PR_26126_004-preview-tool-layout-refinement
 
 ```bash
-codex run "Create PR_26126_003-preview-tool-layout-spec. Convert the preview tool design into a concrete layout spec for tools/preview/index.html. Define exact regions (header, left panel controls, main preview canvas, right panel properties, footer actions). Specify each control placement (input source, validation status, preview mode selector, zoom, background toggle, export buttons). Include DOM structure outline (ids/classes only, no implementation), state model (toolState shape), and interaction flows (load -> validate -> render -> export). No runtime code. Do not modify samples. Place doc under docs/pr/PR_26126_003-preview-tool-layout-spec.md and produce required review artifacts."
+codex run "Create PR_26126_004-preview-tool-layout-refinement. Update the preview tool layout spec to explicitly use Palette Manager as the base layout and interaction pattern (panel structure, control grouping, header usage). Add requirement: center column must include a 'last generated preview' section at the bottom showing the most recent rendered image. Define its placement, sizing, and behavior (replaces on new render, no history, no fallback). Keep strict JSON input rules. No implementation code. Do not modify samples. Update docs/pr/PR_26126_003-preview-tool-layout-spec.md and produce review artifacts."
 ```
 
 ## Validation Commands
 
 ```bash
 git diff --check -- docs/pr/PR_26126_003-preview-tool-layout-spec.md docs/dev/codex_commands.md docs/dev/commit_comment.txt
-node --input-type=module <write PR-scoped review artifacts>
+npm run codex:review-artifacts
 ```
 
 ## Playwright
 
-No Playwright impact. This PR is a documentation/layout-spec-only PR for the Preview tool and does not modify implementation code.
+No Playwright impact. This PR refines documentation/layout specification only and does not modify implementation code.
 
 ## Full Samples
 

docs/dev/commit_comment.txt

@@ -1 +1 @@
-Add Preview tool layout spec - PR_26126_003-preview-tool-layout-spec
+Refine Preview tool layout spec from Palette Manager pattern - PR_26126_004-preview-tool-layout-refinement

docs/dev/reports/codex_changed_files.txt

@@ -1,16 +1,10 @@
 # git status --short
 M docs/dev/codex_commands.md
  M docs/dev/commit_comment.txt
-?? docs/pr/PR_26126_003-preview-tool-layout-spec.md
+ M docs/pr/PR_26126_003-preview-tool-layout-spec.md
 
 # git diff --stat
-docs/dev/codex_commands.md  | 10 +++++-----
- docs/dev/commit_comment.txt |  2 +-
- 2 files changed, 6 insertions(+), 6 deletions(-)
-
-# New design doc diff --stat
-.../pr/PR_26126_003-preview-tool-layout-spec.md    | 619 +++++++++++++++++++++
- 1 file changed, 619 insertions(+)
-
-# Scope note
-PR_26126_003 is documentation/layout-spec only. No samples or runtime code were modified.
+docs/dev/codex_commands.md                       |   8 +-
+ docs/dev/commit_comment.txt                      |   2 +-
+ docs/pr/PR_26126_003-preview-tool-layout-spec.md | 149 +++++++++++++++++++++--
+ 3 files changed, 141 insertions(+), 18 deletions(-)