Split technical questions into per-class decks

DESIGN.md

@@ -491,28 +491,43 @@ output artifacts.
 
 ```
 anki/
-  amateurfunk-technische-kenntnisse.apkg          (~2.5 MB, 1374 cards)
-  amateurfunk-betriebliche-kenntnisse.apkg        (~130 KB,  172 cards)
-  amateurfunk-kenntnisse-von-vorschriften.apkg    (~75 KB,   204 cards)
+  amateurfunk-technische-kenntnisse-n.apkg        (195 cards)
+  amateurfunk-technische-kenntnisse-e.apkg        (463 cards)
+  amateurfunk-technische-kenntnisse-a.apkg        (716 cards)
+  amateurfunk-betriebliche-kenntnisse.apkg        (172 cards)
+  amateurfunk-kenntnisse-von-vorschriften.apkg    (204 cards)
 ```
 
-One `.apkg` per top-level Prüfungsteil. The card counts match the
-study pools from §3 axis 1: Technische = 1374 (cumulative N+E+A);
-Betriebliche = 172 (shared across all candidates); Vorschriften = 204
-(also shared). License class is conveyed via tags
-(`klasse-N` / `klasse-E` / `klasse-A`), not separate packages —
-Anki users browse decks by topic and filter by class.
+Five `.apkg` files. Betriebliche and Vorschriften are shared across
+every candidate (class-1-only in the data per §3 axis 2) and stay as
+one deck each. Technische is fanned out per license class using a
+**strict equality split** on the question's `class` field — class-1
+questions land in the N deck only, class-2 in E only, class-3 in A
+only. The card counts therefore equal the new-at-this-class slices
+from §3, not the cumulative study pools: a candidate studying for
+class E imports Technische-N + Technische-E + Betriebliche +
+Vorschriften.
+
+The Technische deck names use Anki's `::` hierarchy separator
+(`Amateurfunk::Technische Kenntnisse::N`) so the three decks render
+as children of a shared parent in Anki's deck browser. The
+`klasse-N` / `klasse-E` / `klasse-A` tag is still emitted on every
+note — redundant within each Technische deck but useful in Betr/Vor
+for in-Anki filtering, and harmless besides.
 
 ### Steps
 
 1. **Load** the latest catalog: follow `manifest-latest.json` to a
    per-edition directory, read the catalog JSON, the per-edition
    `manifest.json`, and index the `svgs/` folder.
-2. **Categorize** the question tree into three `Category` objects,
-   one per top-level Prüfungsteil. Each category carries the flat
-   list of every question that lives anywhere under it, along with
-   each question's path through the section tree (used for the card
-   breadcrumb and the path tags).
+2. **Categorize** the question tree into five `Category` objects.
+   Betriebliche and Vorschriften get one each. Technische is
+   additionally split into three sub-categories (one per license
+   class) via a strict equality match on the question's `class`
+   field. Each category carries the flat list of every question that
+   lives anywhere under it, along with each question's path through
+   the section tree (used for the card breadcrumb and the path
+   tags).
 3. **For each category, render every question** as an Anki note:
    - Compute a stable per-question seed from `--seed` + question
      number; shuffle the A/B/C/D choices using it. The displayed
@@ -594,13 +609,19 @@ byte-identical sha256 on each `.apkg`. Verified during review.
 - **Slug for filenames.** `slugify()` maps German umlauts and ß
   to ASCII digraphs before NFKD-normalizing the rest, then keeps
   only `[a-z0-9-]`. Yields readable, sortable filenames
-  (`amateurfunk-technische-kenntnisse.apkg`).
+  (`amateurfunk-technische-kenntnisse-n.apkg`). The three
+  Technische decks append the class letter (`-n`, `-e`, `-a`)
+  to the shared base slug; Betriebliche and Vorschriften use the
+  base slug as-is.
 - **Tags.** Each note carries `klasse-N|E|A` plus
   `pfad-<slugified-section>` for every section level below the
-  top-level Prüfungsteil. Per-question number tags are
-  deliberately *not* emitted — they would create ~1750 singletons
-  in Anki's tag tree, and the number is already in the dedicated
-  `Number` field for search.
+  top-level Prüfungsteil. The `klasse-*` tag is redundant within
+  the three Technische decks (every card already shares one class)
+  but is still emitted there for uniformity, and remains the
+  primary filter axis inside the Betriebliche/Vorschriften decks.
+  Per-question number tags are deliberately *not* emitted — they
+  would create ~1750 singletons in Anki's tag tree, and the number
+  is already in the dedicated `Number` field for search.
 - **Breadcrumb consistency.** The visible card breadcrumb and the
   stored `Path` field both go through one `display_path()`
   helper, so they never drift. The boilerplate
@@ -618,8 +639,11 @@ Network-free, fixture-driven. Real Anki is NOT required to
 verify the output — tests open the `.apkg` ZIP directly, parse
 the embedded SQLite, and check structural invariants.
 
-- Top-level structure: one `.apkg` per Prüfungsteil; expected
-  filename slugs.
+- Top-level structure: five `.apkg` files (Betriebliche +
+  Vorschriften + Technische×{N,E,A}); expected filename slugs.
+- Technische class partition: each Technische deck contains
+  exactly the questions whose `class` field matches that letter,
+  and no others.
 - Note count and field shape per category.
 - Tag mapping: a class-1 question carries `klasse-N`, no
   `nummer-*` tags.