Clear terminal output buffers to prevent memory leaks

[hannesrudolph]

Closes #10666

Summary

• avoid retaining large command output by trimming buffers in BaseTerminalProcess
• clear stored output when TerminalProcess and ExecaTerminalProcess finish running commands

[roomote]

Thank you for working on this memory leak fix! I've reviewed the changes and found some critical issues that need to be addressed before this can be merged. The main concern is that the memory leak may not be fully resolved due to the implementation logic.

[daniel-lxs]

Hey! I traced through the code and I think there's a timing issue here.

The problem is this line:

this.lastRetrievedIndex = this.fullOutput.length

This marks all output as "retrieved" immediately after the command completes, but getEnvironmentDetails() hasn't had a chance to actually call getUnretrievedOutput() yet.

What happens:

1. Command completes → process gets added to completedProcesses queue ✓
2. Buffer gets cleared (PR change)
3. Later, getEnvironmentDetails() tries to get output from completed processes
4. cleanCompletedProcessQueue() removes the process because hasUnretrievedOutput() now returns false
5. The AI never sees the terminal output

This breaks the "Inactive Terminals with Completed Process Output" section in getEnvironmentDetails.ts.

The fix would be to not force lastRetrievedIndex = fullOutput.length - just call trimRetrievedOutput() by itself, which will only clear when output has actually been consumed via getUnretrievedOutput().

[hannesrudolph]

Hey! I traced through the code and I think there's a timing issue here.

The problem is this line:

this.lastRetrievedIndex = this.fullOutput.length

This marks all output as "retrieved" immediately after the command completes, but getEnvironmentDetails() hasn't had a chance to actually call getUnretrievedOutput() yet.

What happens:

1. Command completes → process gets added to completedProcesses queue ✓
2. Buffer gets cleared (PR change)
3. Later, getEnvironmentDetails() tries to get output from completed processes
4. cleanCompletedProcessQueue() removes the process because hasUnretrievedOutput() now returns false
5. The AI never sees the terminal output

This breaks the "Inactive Terminals with Completed Process Output" section in getEnvironmentDetails.ts.

The fix would be to not force lastRetrievedIndex = fullOutput.length - just call trimRetrievedOutput() by itself, which will only clear when output has actually been consumed via getUnretrievedOutput().

@roomote address this please.