Challenge 1: Where Three Specific kvstore Pieces Came From — Possible Solution
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(a) THE SEPARATE-CHAINING COLLISION STRATEGY comes from c3-2 (Building
    Data Structures From Scratch). That chapter built the exact
    bucket-of-linked-list structure kvstore's HashTable reuses
    directly -- when two keys hash to the same bucket index, both are
    appended to that bucket's own linked list rather than one
    overwriting the other, exactly as c3-2 established and justified.

(b) THE SAVE-FILE FORMAT comes from c2-6 (File I/O). The one-line-
    per-entry "key=value\n" text format, written with fopen/fprintf in
    "w" mode and read back on startup, is a direct application of that
    chapter's fopen/fprintf/fgets material -- specifically the text-mode
    (not binary-mode) file handling it covered.

(c) THE DISCIPLINE OF FREEING EVERY KEY AND VALUE ON PROGRAM EXIT comes
    from c2-2 (Dynamic Memory), applied at the scale c3-2 later extended
    it to (many separate allocations, not just one). Every string
    duplicated onto the heap when a key or value is inserted needs its
    own matching free -- the exact malloc/free pairing discipline c2-2
    established as this track's central safety-tradeoff lesson.

WHY THIS WORKS AS AN ANSWER
------------------------------
This correctly attributes each piece to its actual origin chapter (not
just "somewhere in Course 2/3") and briefly restates what that chapter
specifically taught that the capstone is now applying, confirming real
understanding of how the pieces connect rather than just naming
chapter numbers.