docs: add VitePress documentation site

- Add docs directory with VitePress configuration
- Add GitHub Actions workflow for docs build and deploy
- Support bilingual (English/Chinese) documentation
- Include search, custom theme, and responsive design

docs/features/spec.md

@@ -0,0 +1,96 @@
+# Spec System
+
+## One-Liner
+
+**The Spec System is an automatic constraint injection mechanism** — Through specification documents defined in YAML frontmatter, relevant constraints are automatically loaded at the start of AI sessions, ensuring AI follows project coding standards and architectural requirements.
+
+---
+
+## Pain Points Solved
+
+| Pain Point | Current State | Spec System Solution |
+|------------|---------------|---------------------|
+| **AI ignores standards** | CLAUDE.md written but AI ignores it after 5 turns | Hook auto-injection, every session carries specs |
+| **Standards scattered** | Coding conventions in different places, hard to maintain | Unified in `.workflow/specs/*.md` |
+| **Context loss** | New session requires re-explaining constraints | Spec auto-loads based on task context |
+| **Inconsistent code** | Different developers write different styles | Shared Spec ensures consistency |
+
+---
+
+## vs Traditional Methods
+
+| Dimension | CLAUDE.md | `.cursorrules` | **Spec System** |
+|-----------|-----------|----------------|-----------------|
+| Injection | Auto-load but easily truncated | Manual load | **Hook auto-injection, task-precise loading** |
+| Granularity | One large file | One large file | **Per-module files, combined by task** |
+| Cross-session memory | None | None | **Workflow journal persistence** |
+| Team sharing | Single person | Single person | **Git versioned Spec library** |
+
+---
+
+## Core Concepts
+
+| Concept | Description | Location |
+|---------|-------------|----------|
+| **Spec File** | Markdown document with YAML frontmatter | `.workflow/specs/*.md` |
+| **Hook** | Script that auto-injects specs into AI context | `.claude/hooks/` |
+| **Spec Index** | Registry of all available specs | `.workflow/specs/index.yaml` |
+| **Spec Selector** | Logic that chooses relevant specs for a task | Built into CCW |
+
+---
+
+## Usage
+
+### Creating a Spec
+
+```markdown
+---
+name: coding-standards
+description: Project coding standards
+triggers:
+  - pattern: "**/*.ts"
+  - command: "/implement"
+  - skill: "code-developer"
+applyTo:
+  - "src/**"
+priority: high
+---
+
+# Coding Standards
+
+## TypeScript Guidelines
+- Use strict mode
+- Prefer interfaces over types
+- ...
+```
+
+### Spec Loading
+
+Specs are automatically loaded based on:
+1. File patterns being edited
+2. Commands being executed
+3. Skills being invoked
+
+---
+
+## Configuration
+
+```yaml
+# .workflow/specs/index.yaml
+specs:
+  - name: coding-standards
+    path: ./coding-standards.md
+    enabled: true
+    
+  - name: api-conventions
+    path: ./api-conventions.md
+    enabled: true
+```
+
+---
+
+## Related Links
+
+- [Memory System](/features/memory) - Persistent context
+- [CLI Call](/features/cli) - Command line invocation
+- [Dashboard](/features/dashboard) - Visual management