docs: add dormant local/cloud dev-mode design to lark-apps skill

[raistlin042]

Summary

Add design-preview skill documentation for lark-apps local/cloud development modes and the fullstack git-clone setup flow. All referenced commands (+git-credential-*, +db-*, +env-pull, +session-*, +chat, +publish*) are not yet implemented, so every file is explicitly marked "命令未上线 · 暂不启用" and SKILL.md carries the routing design in a dormant block that does not activate intent routing — preventing agents from calling unimplemented commands.

Changes

• skills/lark-apps/SKILL.md: add a dormant "开发模式（规划中 · 命令未上线 · 暂不启用）" section before ## Shortcuts; existing HTML/fullstack flows untouched.
• skills/lark-apps/references/lark-apps-local-setup.md (new): one-time local-dev setup — two entry scenarios (create-from-scratch / existing appId) converging on git-credential-init → clone → cd.
• skills/lark-apps/references/lark-apps-local-dev.md (new): local dev mode capability list (+db-* / +env-pull / +publish*).
• skills/lark-apps/references/lark-apps-cloud-dev.md (new): cloud dev mode capability list (+session-* / +chat / +publish).

Test Plan

• validate passed (build / vet / unit / integration)
• sandbox E2E passed (2/2 — existing fullstack dry-run regression; no new E2E, no command changes)
• acceptance-reviewer passed (4 scenarios — dormant markings prevent agents from calling unreleased commands; HTML/fullstack flows no regression)
• sandbox skillave passed (9/9 — 4 dev-mode cases verify the agent replies "暂未上线" without calling unreleased commands, + 5 fullstack regression)
• N/A: no runtime command introduced (docs-only); real command contracts will be added when the commands ship

Related Issues

N/A