refactor: 切换 OpenSpec workflow 从 spec-driven 到 fast-drive

- 新增 fast-drive 自定义 schema 及模板（design.md、tasks.md）
- 更新 config.yaml schema 为 fast-drive，调整 rules
- 重构 proposal-review 和 apply-review 提示词适配 fast-drive
- 删除 spec-review 提示词（fast-drive 不需要 spec 审查）
- 删除 openspec/specs/ 下的稳定规范文件
- 更新 README 和 DEVELOPMENT.md 相关描述

openspec/schemas/fast-drive/templates/tasks.md

@@ -0,0 +1,19 @@
+## 1. Context Review
+
+- [ ] 1.1 Read design.md and identify scope, requirements, decisions, guardrails, and open questions
+- [ ] 1.2 Review relevant artifacts and references listed in Affected Areas
+
+## 2. Execution
+
+- [ ] 2.1 Execute first concrete work item from design.md
+- [ ] 2.2 Execute next concrete work item from design.md
+
+## 3. Validation
+
+- [ ] 3.1 Run required validation from Verification Plan
+- [ ] 3.2 Perform quality checks required by the project or workflow
+- [ ] 3.3 Perform required manual review or acceptance checks from Verification Plan
+
+## 4. Documentation / Communication
+
+- [ ] 4.1 Update relevant documentation, runbooks, communication materials, or project references if behavior, process, interface, configuration, or usage changed