Randomize questions on every Anki regen

Also make explanation section slightly more readable

CLAUDE.md

@@ -83,8 +83,11 @@ data/ ──[Stage 2: amateurfunk_anki.py]──► anki/
    block is appended to the back; a "low confidence" badge shows for
    entries with `confidence < 7`.
 4. Hand-roll the v11 Anki collection (SQLite + JSON config) and
-   package it as a `.apkg` ZIP with deterministic timestamps. Same
-   input → byte-identical output across runs.
+   package it as a `.apkg` ZIP with deterministic timestamps. By
+   default each build mints a fresh shuffle seed, so answers are
+   reshuffled every run. Pass `--seed` (and `--epoch`) for the
+   reproducible-build contract: same catalog + same seed + same
+   timestamp → byte-identical output across runs.
 
 The Anki design decisions (shuffle seeding, deterministic build epoch,
 SVG dark-mode handling, schema choices) live in `DESIGN.md` §7.