Summary

Reduce persistent background work from Git ref enumeration and preview port discovery while preserving freshness when users interact with either surface.

What Changed

• Revalidate only the first Git-ref page every 20 seconds instead of polling every retained page every five seconds
• Load cursor pages once per connected generation and expire inactive ref atoms after 30 seconds
• Refresh local and remote refs immediately when the composer branch or Diff comparison menu opens
• Replay the latest preview-discovery snapshot instead of running a duplicate subscription scan
• Serialize snapshot replay with concurrent broadcasts so subscribers cannot regress to stale results
• Roll back listener registration when initial snapshot replay fails so a defective subscriber cannot block later broadcasts
• Serialize port scans before publication so an older slow scan cannot overwrite a newer snapshot
• Scan immediately when managed terminal process sets change and ignore unchanged registrations or redundant removals
• Run the broad port-discovery safety net every 20 seconds while idle and every 10 seconds when a listener is known

Why

During extended use, T3 Code's resident memory climbed past 6 GB even while idle, while the renderer sustained roughly 10% CPU and the machine became noticeably warm around the CPU and GPU clusters. That pattern indicated that background work was continuing without user interaction and could compound renderer and resource pressure over long sessions.

Diagnostics identified two repeatable sources of idle churn: every retained Git-ref query, including each loaded pagination page, owned its own five-second listRefs revalidation loop, while preview discovery launched a broad lsof scan every three seconds. Preview subscription initialization could also scan twice, and unchanged terminal process registrations caused redundant probes. The new schedules reduce that steady subprocess load while immediate menu refreshes, terminal-process-triggered scans, and adaptive safety-net polling preserve freshness at interaction time.

Validation

• Port scanner focused suite passed with 8 tests, including concurrent replay ordering, failed-replay listener cleanup, and concurrent scan serialization
• Targeted server and client-runtime type checks passed
• Isolated authenticated web verification loaded local, worktree, and remote refs when the branch selector opened
• git diff --check passed

Proof

No standalone proof artifacts were captured; the isolated browser verification is summarized above.