♻️ refactor: 需求与计划改走 ECC 工作流，PRD/计划落到 .claude 目录

头脑风暴、续聊、实施三套 prompt（vscode / jetbrains / tui 同步）从 superpowers 的 brainstorming 与 /goal 换成 /ecc:plan-prd、/ecc:plan、/ecc:tdd-workflow。spec/plan 路径固定为 .claude/prds/<slug>.prd.md 与 .claude/plans/<slug>.plan.md，slug 派生去掉 .prd.md / .plan.md 后缀；worktreePath 测试挪到 test/ 目录。

Claude-Session: https://claude.ai/code/session_01QWxLb6X8Vd2G5vHnp6R7qm

vscode/webview-ui/src/types.ts

@@ -29,13 +29,13 @@ export interface Issue {
   /**
    * Optional workspace-relative path to the spec file for this issue, as
    * surfaced from the Claude session transcript. Lives under
-   * `docs/superpowers/specs/*.md`.
+   * `.claude/prds/<slug>.prd.md`.
    */
   specFile?: string
   /**
    * Optional workspace-relative path to the plan file for this issue, as
    * surfaced from the Claude session transcript. Lives under
-   * `docs/superpowers/plans/*.md`.
+   * `.claude/plans/<slug>.plan.md`.
    */
   planFile?: string
   /** Optional workspace-relative path to the generated PR diff summary. */