[Refactor] Extract system prompt & context management from Task.ts #25

Parent Issue

Part of #8 — Code Refactor on Monolith Files

Related upstream issues

• Cline exhausts context window on src/core/task/index.ts (≈4 000 LOC) cline/cline#3095 — AI agents exhaust their context window loading the full monolith; this cluster is a primary contributor

Summary

Extract the system prompt construction, context condensing/truncation, and environment detail logic from src/core/task/Task.ts into a dedicated module.

Scope

Methods to extract:

• condenseContext()
• getSystemPrompt()
• handleContextWindowExceededError()
• buildCleanConversationHistory()
• getEnabledMcpToolsCount()
• getFilesReadByRooSafely()
• getCurrentProfileId()

State owned: None directly — read-only access to other state

Estimated size: ~300–400 lines

Notes

This cluster integrates with MCP, prompt generation, and context management subsystems but owns no mutable state itself, making it a clean extraction target. Resolving this directly reduces the file size AI coding agents must load when working on Task.ts (see cline/cline#3095).

Constraints (from #8)

• Preserve call signatures and return types
• Avoid circular dependencies with MCP and prompt modules
• Run type checks after extraction
• One extraction per commit