Working tree, staging, commit — the model AI breaks first — step 8 of 9

Build a small status summarizer. Write summarize(status) that takes a parsed git status dict and returns a one-line string of the form:

<branch>: <staged> staged, <modified> modified, <untracked> untracked

Where each <n> is the count of items in the matching list.

Then call it on the provided status and print the result.

Expected output:

feature/login: 2 staged, 1 modified, 1 untracked