Add PAGX module with spec, importer, exporter, SVG converter, and web playground

.codebuddy/commands/cr.md

@@ -67,8 +67,8 @@ done
 # 拉取最新的 main 分支
 git fetch origin main
 
-# 当前分支相对 origin/main 的完整变更（已提交 + 暂存区 + 工作区的最终结果）
-git diff origin/main
+# 当前分支相对 origin/main 分叉点的完整变更（已提交 + 暂存区 + 工作区的最终结果）
+git diff $(git merge-base origin/main HEAD)
 
 # 查看文件状态（用于识别未跟踪文件）
 git status
@@ -105,8 +105,8 @@ cd /tmp/pr-review-{pr_number}
 # 拉取最新的 main 分支
 git fetch origin main
 
-# 当前分支相对 origin/main 的完整变更
-git diff origin/main
+# 当前分支相对 origin/main 分叉点的完整变更
+git diff $(git merge-base origin/main HEAD)
 
 gh pr view {pr_number} --comments
 ```
@@ -233,3 +233,4 @@ echo "已清理临时审查环境"
 9. **潜在风险**：是否引入回归风险或影响其他模块
 10. **模块架构**：模块职责是否清晰，依赖方向是否合理（如核心模块不应反向依赖平台特定实现）
 11. **整体设计**：结合关联代码评估修改后的整体合理性，必要时建议扩大修改范围
+

.codebuddy/commands/pr.md

@@ -11,7 +11,6 @@ description: 提交 PR - 自动识别新建或追加提交
 ## 前置检查
 
 ```bash
-git fetch origin main && \
 CURRENT_BRANCH=$(git branch --show-current) && \
 echo "CURRENT_BRANCH:$CURRENT_BRANCH" && \
 gh pr list --head "$CURRENT_BRANCH" --state open --json number,url && \

.codebuddy/rules/Code.md

@@ -6,8 +6,8 @@ alwaysApply: true
 ## 编码规范
 
 - 对话用中文，代码和注释用英语
-- 所有说明文件、方案设计文件统一放在 `.codebuddy/designs/` 目录（已加入 .gitignore，不参与提交）
-- 新需求禁止直接编码，先输出详细方案设计文件，穷尽疑问向用户提问，用户明确确认后再按方案编码
+- 永远优先追求答案的正确性而不只是迎合用户的具体要求，特别是当用户的具体要求和正确性有冲突时要及时指出来
+- 新需求的编码任务禁止直接编码，先输出关键接口和伪代码，穷尽所有疑问向用户提问，方案确认后才可编码
 - 复用项目已有功能，保持变更简洁，避免重复代码
 - 重构时审查关联代码合理性，顺带清理冗余，不考虑向后兼容
 - 版权声明里的年份对新增的文件要使用当前年份（如 `Copyright (C) 2026 Tencent`），已有文件保持原年份不变

.codebuddy/skills/pagx-optimize/SKILL.md

@@ -0,0 +1,122 @@
+---
+name: pagx-optimize
+description: Optimize PAGX file structure by removing redundancy, merging shared painters, extracting reusable resources, and improving readability. Use this skill when asked to optimize, simplify, or clean up a PAGX file.
+argument-hint: "[file-path]"
+---
+
+# PAGX File Structure Optimization
+
+This skill provides a systematic checklist for optimizing PAGX file structure. The goals are
+to simplify file structure, reduce file size, and improve rendering performance.
+
+## Fundamental Constraint
+
+**All optimizations must preserve the original design appearance.** This is a hard requirement
+that overrides any individual optimization direction below.
+
+- **Allowed**: Structural transformations that produce identical or near-identical rendering
+  (minor pixel-level differences from node reordering or painter merging are acceptable).
+- **Allowed**: Removing provably invisible content — elements entirely outside the canvas
+  bounds, unused resources, zero-width strokes, fully transparent elements, and other content
+  that contributes nothing to the final rendered image.
+- **Forbidden**: Modifying any parameter that affects design intent — blur radius, spacing,
+  density, colors, alpha, gradient stops, font sizes, shadow offsets, stroke widths, or any
+  other visual attribute — unless the user explicitly approves the change.
+- **Forbidden**: Reducing Repeater density (increasing spacing), lowering blur values, changing
+  opacity, or simplifying geometry in ways that alter the visual result, even if the change
+  seems minor. These are design decisions, not optimization decisions.
+- **When in doubt**: If an optimization might change the rendered appearance, do not apply it.
+  Instead, describe the potential optimization and its visual impact to the user, and ask for
+  explicit approval before proceeding.
+
+---
+
+## Optimization Checklist
+
+### Structure Cleanup (Sections 1-7)
+
+| # | Optimization | When to Apply |
+|---|--------------|---------------|
+| 1 | Move Resources to End | `<Resources>` appears before layer tree |
+| 2 | Remove Empty Elements | Empty `<Layer/>`, empty `<Resources>`, `width="0"` strokes |
+| 3 | Omit Default Values | Attributes explicitly set to spec default |
+| 4 | Simplify Transforms | Translation-only matrix, identity matrix, cascaded translations |
+| 5 | Normalize Numerics | Scientific notation near zero, trailing decimals, short hex |
+| 6 | Remove Unused Resources | Resource `id` has no `@id` reference |
+| 7 | Remove Redundant Wrappers | Group/Layer with no attributes wrapping single element |
+
+> For detailed examples and default value tables, read `references/structure-cleanup.md`.
+
+### Painter Merging (Sections 8-9)
+
+| # | Optimization | When to Apply |
+|---|--------------|---------------|
+| 8 | Merge Geometry Sharing Identical Painters | Multiple geometry elements use same Fill/Stroke |
+| 9 | Merge Painters on Identical Geometry | Same geometry appears twice with different painters |
+
+**Critical caveat (Section 8)**: Different geometry needing different painters must be isolated
+with Groups. This is the most common source of errors.
+
+> For detailed examples and scope isolation patterns, read `references/painter-merging.md`.
+
+### Resource Reuse (Sections 10-14)
+
+| # | Optimization | When to Apply |
+|---|--------------|---------------|
+| 10 | Composition Reuse | 2+ identical layer subtrees differing only in position |
+| 11 | PathData Reuse | Same path data string appears 2+ times |
+| 12 | Color Source Sharing | Identical gradient definitions inline in multiple places |
+| 13 | Replace Path with Primitive | Path describes a Rectangle or Ellipse |
+| 14 | Remove Full-Canvas Clips | Clip mask covers entire canvas |
+
+> For detailed examples and coordinate conversion formulas, read `references/resource-reuse.md`.
+
+### Performance Optimization (Section 15)
+
+**Rendering Cost Model**:
+- **Repeater**: N copies = N× full rendering cost (no GPU instancing)
+- **Nested Repeaters**: Multiplicative (A×B elements)
+- **BlurFilter / DropShadowStyle**: Cost proportional to blur radius
+- **Dashed Stroke under Repeater**: Dash computation per copy
+- **Layer vs Group**: Layer creates extra surface; Group is lighter
+
+**Two categories**:
+1. **Equivalent (auto-apply)**: Downgrade Layer to Group, clip Repeater to canvas bounds
+2. **Suggestions (never auto-apply)**: Reduce density, lower blur, simplify geometry
+
+> For detailed optimization techniques, read `references/performance.md`.
+
+---
+
+## Appendix: Core Concepts
+
+### Painter Scope
+
+Painters (Fill / Stroke) render **all geometry accumulated in the current scope up to that
+painter's position**. Subsequent painters continue to render the same geometry.
+
+### Group Scope Isolation
+
+Group creates an isolated scope. Internal geometry accumulates only within the Group, and
+after the Group ends, its geometry propagates upward to the parent scope.
+
+### Layer vs Group
+
+| Feature | Layer | Group |
+|---------|-------|-------|
+| Geometry propagation | No (boundary) | Yes (to parent) |
+| Styles / Filters / Mask | Supported | Not supported |
+| Composition / BlendMode | Supported | Not supported |
+| Transform | matrix | position/rotation/scale |
+
+**Selection rule**: Use Layer for styles/filters/mask/composition/blendMode. Otherwise prefer Group.
+
+> For DropShadowStyle scope and color source coordinate system, see `references/painter-merging.md`
+> and `references/resource-reuse.md` respectively.
+
+---
+
+## PAGX Specification Quick Reference
+
+For complete attribute defaults, required attributes, and enumeration values extracted from
+the PAGX spec, see `references/pagx-quick-reference.md`.