feat: 品牌替换 + 启动优化 + AGENTS.md 模板定制

- 品牌替换：OpenCode/opencode → AirCoding/aircoding（16+ 文件）
- Logo ASCII art：修复 left/right 行数不匹配导致的启动崩溃
- 启动诊断：添加 OPENCODE_PRINT_TIMING 计时探针
- dev 模式默认 --pure 跳过外部插件加载
- AGENTS.md 模板：追加 AirCoding 多 Agent 专项段落
- architect prompt + plugin：强化 AGENTS.md 产出验证

.opencode/command/learn.md

@@ -0,0 +1,42 @@
+---
+description: Extract non-obvious learnings from session to AGENTS.md files to build codebase understanding
+---
+
+Analyze this session and extract non-obvious learnings to add to AGENTS.md files.
+
+AGENTS.md files can exist at any directory level, not just the project root. When an agent reads a file, any AGENTS.md in parent directories are automatically loaded into the context of the tool read. Place learnings as close to the relevant code as possible:
+
+- Project-wide learnings → root AGENTS.md
+- Package/module-specific → packages/foo/AGENTS.md
+- Feature-specific → src/auth/AGENTS.md
+
+What counts as a learning (non-obvious discoveries only):
+
+- Hidden relationships between files or modules
+- Execution paths that differ from how code appears
+- Non-obvious configuration, env vars, or flags
+- Debugging breakthroughs when error messages were misleading
+- API/tool quirks and workarounds
+- Build/test commands not in README
+- Architectural decisions and constraints
+- Files that must change together
+
+What NOT to include:
+
+- Obvious facts from documentation
+- Standard language/framework behavior
+- Things already in an AGENTS.md
+- Verbose explanations
+- Session-specific details
+
+Process:
+
+1. Review session for discoveries, errors that took multiple attempts, unexpected connections
+2. Determine scope - what directory does each learning apply to?
+3. Read existing AGENTS.md files at relevant levels
+4. Create or update AGENTS.md at the appropriate level
+5. Keep entries to 1-3 lines per insight
+
+After updating, summarize which AGENTS.md files were created/updated and how many learnings per file.
+
+$ARGUMENTS