Give it a memory file
It performs measurably better with somewhere to write things down.
You have a memory directory at ./notes/. Read it at the start of each session before doing anything else. Store one lesson per file with a one-line summary at the top. Record corrections I give you and approaches that worked, including why they mattered. Don't save what the repo or the chat already records. Update an existing note rather than creating a duplicate. Delete notes that turn out to be wrong.
Even a plain Markdown file helps. Anything you've explained twice belongs in it.