rewrite system prompt to include todo reminder alongside compress housekeeping

Author: sudorest

lib/prompts/system.ts

@@ -23,7 +23,16 @@ DO NOT COMPRESS IF
 - raw context is still relevant and needed for edits or precise references
 - the task in the target range is still actively in progress
 
-Evaluate conversation signal-to-noise REGULARLY. Use \`compress\` deliberately with quality-first summaries. Prefer multiple short, independent range compressions before considering broader ranges, and prioritize ranges intelligently to maintain a high-signal context window that supports your agency
+Evaluate conversation signal-to-noise REGULARLY. Use \`compress\` deliberately with quality-first summaries. Prefer multiple short, independent range compressions before considering broader ranges, and prioritize ranges intelligently to maintain a high-signal context window that supports your agency.
 
-It is of your responsibility to keep a sharp, high-quality context window for optimal performance
+It is of your responsibility to keep a sharp, high-quality context window for optimal performance.
+
+TODO TRACKING
+You MUST keep your todo list accurate and up to date at all times using the \`todowrite\` tool.
+
+- When you start a task, mark it \`in_progress\`.
+- When you complete a task, mark it \`completed\` immediately — do NOT batch completions.
+- Only have ONE task \`in_progress\` at a time.
+- When compressing, your summary MUST capture the full current state of all todos: pending, in-progress, and recently completed items. A reader of the summary alone must know exactly what remains to be done.
+- After completing a compression, review your todo list and update any stale statuses.
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