fix(skills): 补回 #56 压缩时误删的实质信息（意图对齐） (#57)

## 摘要 / Summary

### 中文

#56 的复盘修正。上一轮"强改写压缩"把四技能 L1
的**技术属性、使用场景与交互示范当套话一刀切**，造成实质信息丢失（承诺"意图全保留"但未做到）。本 PR 补回：

- **create**：`创建仓库符合 AgentFS v2 规范、git
管理版本（可治理/可追溯）`定位；`基础创建`形态（name+description，description 自动填充 persona
L0）；需求收集的**引导问题示例**（"起什么名字？/主要负责什么？"…）；企业部署/开发者原型使用场景。
- **update**：`agent 目录 git 管理版本、历史可追溯`定位 + 使用场景。
- **discover**：使用场景（浏览/新用户/找替代）+ `语义匹配而非关键词搜索`。
- **delete**：使用场景（清理/测试/释放存储）。

根因：L1 混着实质技术属性与营销套话、使用场景是触发判据、引导问题是交互示范，不该按"只留独有信息"一刀切。补回后仍保留结构性压缩（zh
正文合计仍降 ~64%）。版本 create 2.5.2 / update 3.1.3 / delete 2.5.2 / discover
2.6.2，manifest 1.2.13，中英双份同步、重算 source_hash（validate-i18n 通过）。

### English

Post-mortem fix for #56. The previous aggressive compression treated the
skills' L1 technical attributes, use cases, and interaction demos as
boilerplate and cut them in a blanket way, dropping substantive
information (the "all intent preserved" claim wasn't fully met). This PR
restores: create's AgentFS-v2 / git-version-management positioning, the
"basic create" form (name+description auto-filling persona L0), the
requirement-gathering prompt questions, and enterprise/developer use
cases; update's git-versioned/traceable positioning and use cases;
discover's use cases and "semantic match, not keyword search"; delete's
use cases. Root cause: L1 mixed real technical attributes with marketing
boilerplate, use cases are trigger cues, and prompt questions are
interaction demos — none should have been blanket-cut. Structural
compression is retained (zh bodies still ~64% smaller). Versions bumped,
manifest 1.2.13, both locales synced, source hashes recomputed
(validate-i18n passes).

skills/update-agent/SKILL.md

@@ -3,7 +3,7 @@ name: update-agent
 description: >-
   安全更新现有智能体的配置、人格、原则、技能与记忆，输出可审阅 diff 并在确认后应用与提交。Use when 用户要求修改 Agent
   行为、安装/卸载技能、调整配置、回滚变更或修订规则。
-version: 3.1.2
+version: 3.1.3
 type: meta
 risk_level: low
 status: enabled
@@ -27,7 +27,7 @@ metadata:
       description: >-
         安全更新现有智能体的配置、人格、原则、技能与记忆，输出可审阅 diff 并在确认后应用与提交。Use when 用户要求修改 Agent 行为、安装/卸载技能、调整配置、回滚变更或修订规则。
       body: ./SKILL.zh-CN.md
-      source_hash: sha256:ceab26ea93a41898
+      source_hash: sha256:d33f63306685168e
       translated_by: human
     en-US:
       name: Update Agent
@@ -35,7 +35,7 @@ metadata:
       description: >-
         Safely update an existing Agent's config, persona, principles, skills, and memory, producing reviewable diffs that are applied and committed only after confirmation. Use when the user asks to modify Agent behavior, install/uninstall skills, adjust config, roll back changes, or revise rules.
       body: ./SKILL.md
-      source_hash: sha256:ceab26ea93a41898
+      source_hash: sha256:d33f63306685168e
       translated_by: ai:claude-fable-5
       translated_at: '2026-07-19'
 market:
@@ -69,7 +69,7 @@ Safely modify an Agent's configuration, persona, rules, and skills through natur
 
 ## L1: Overview
 
-Meta-skill: recognize the edit intent → generate a reviewable diff → user confirmation → apply (structured fields via ManageAgent, free-form files via Read/Write) → receipt, with version rollback. Its value is what the tool can't give: diff preview confirmation, two-path orchestration, rollback; structured fields go through ManageAgent's whitelist + schema validation so invalid config never lands.
+Meta-skill: recognize the edit intent → generate a reviewable diff → user confirmation → apply (structured fields via ManageAgent, free-form files via Read/Write) → receipt. Use it to adjust communication style, add/change behavior rules, install/uninstall skills, or batch-upgrade config. The agent directory is version-managed by git with a traceable history, so rollback is supported. Its value is what the tool can't give: diff preview confirmation, two-path orchestration, version rollback; structured fields go through ManageAgent's whitelist + schema validation so invalid config never lands.
 
 ## L2: Detailed Spec