refactor(config): centralize env and provider protocols

[M09Ic]

Summary

• centralize runtime business environment resolution in core/config with explicit precedence
• keep OpenAI-compatible and Anthropic as the only LLM protocols handled by AIScan
• reject vendor provider names and remove legacy LLM/integration environment aliases
• render frontend provider presets such as DeepSeek, OpenRouter, Ollama, and Zhipu; each preset writes only its protocol and Base URL
• pass resolved Tavily, Uncover, TUI, data directory, and Playwright settings through runtime configuration
• separate Uncover credentials from LLM provider terminology
• align Web validation, provider profiles, examples, and documentation with strict two-protocol configuration

Tests

• go test ./core/config ./agent/provider ./pkg/webproto ./pkg/web ./pkg/webagent ./pkg/runner ./tools/scan/engine ./tools/search ./cmd/aiscan ./cmd/agent ./cmd/runner
• go test -tags full ./core/config ./agent/provider ./tools/scan/engine ./tools/playwright ./pkg/runner ./pkg/web ./cmd/aiscan
• git diff --check

Frontend TypeScript reaches the existing cyber-ui CSTX dependency issue only (graphology); no ConfigPanel diagnostics are produced.