feat: initialize ERP base platform (extracted from HMS)

- Stripped 11 business crates (health, ai, dialysis, plugins)
- Cleaned AppState, AppConfig, main.rs from business coupling
- Reduced migrations from 169 to 53 (base-only)
- Removed health_provider trait from erp-core
- Removed business integration tests
- Removed gateway rate limiting middleware
- Base capabilities: auth, RBAC, JWT, config, workflow, message, plugin, audit, crypto, RLS, multi-tenant

Cargo check: OK
Cargo test: OK

config/default.toml

@@ -0,0 +1,81 @@
+[server]
+host = "0.0.0.0"
+port = 3000
+
+[database]
+url = "__MUST_SET_VIA_ENV__"
+max_connections = 20
+min_connections = 5
+
+[redis]
+url = "__MUST_SET_VIA_ENV__"
+
+[jwt]
+secret = "__MUST_SET_VIA_ENV__"
+access_token_ttl = "15m"
+refresh_token_ttl = "7d"
+
+[auth]
+super_admin_password = "__MUST_SET_VIA_ENV__"
+
+[log]
+level = "info"
+
+[cors]
+# Comma-separated allowed origins. Use "*" for development only.
+allowed_origins = "http://localhost:5173,http://localhost:5174,http://localhost:5175,http://localhost:5176,http://localhost:3000"
+
+[wechat]
+appid = "__MUST_SET_VIA_ENV__"
+secret = "__MUST_SET_VIA_ENV__"
+# dev_mode = true 跳过 jscode2session，允许微信开发者工具模拟器登录
+# 生产环境必须为 false（默认）
+dev_mode = false
+
+[health]
+aes_key = "__MUST_SET_VIA_ENV__"
+hmac_key = "__MUST_SET_VIA_ENV__"
+
+[crypto]
+kek = "__MUST_SET_VIA_ENV__"
+
+[ai]
+default_provider = "claude"
+api_key = ""
+base_url = "https://api.anthropic.com"
+model = "claude-sonnet-4-6"
+max_tokens = 2048
+temperature = 0.3
+cache_ttl_seconds = 604800
+rate_limit_patient_daily = 10
+quota_check_enabled = true
+
+[ai.providers.claude]
+provider_type = "claude"
+api_key_env = "ANTHROPIC_API_KEY"
+base_url = "https://api.anthropic.com"
+default_model = "claude-sonnet-4-6"
+max_tokens = 2048
+temperature = 0.3
+is_enabled = true
+
+[ai.providers.openai]
+provider_type = "openai"
+api_key_env = "OPENAI_API_KEY"
+base_url = "https://api.openai.com"
+default_model = "gpt-4o"
+max_tokens = 2048
+temperature = 0.3
+is_enabled = false
+
+[ai.providers.ollama]
+provider_type = "ollama"
+base_url = "http://localhost:11434"
+default_model = "qwen2.5:7b"
+max_tokens = 2048
+temperature = 0.3
+is_enabled = false
+
+[storage]
+upload_dir = "./uploads"
+max_file_size = "10MB"