Add Lesen & Schreiben A1 Abschnitt A (Personen)

First section of the reading/writing supplementary book: self-
introductions, heißen/kommen/wohnen/sein conjugation, a family
registration form (reading + guided writing), sentence/word boundaries,
capitalization rules, and formal vs. informal address (pp. 5-11).

This PDF's official Lösungen pages are missing from every copy found
online (all mirrors trace to the same cropped scan). Answers in this
section are marked [abgeleitet] (derived, unambiguous) or [offen]
(genuinely open-ended) rather than sourced from a publisher key.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Ergaenzung/INDEX.md

@@ -51,5 +51,14 @@ Ordinalzahlen/date-writing (Q).
 
 ## Lesen & Schreiben A1 (`lesen-schreiben-a1/`)
 
-| Einheit | Title/Topic | Relates to Menschen Lektion(en) | Status |
-|---|---|---|---|
+Filed one section per lettered Abschnitt (A–H), same convention as
+Wortschatz & Grammatik. **This book's PDF is missing its official
+Lösungen (answer key) pages — every copy found online was cropped the
+same way before the answer key.** Each `abschnitt-X.md` marks its own
+answers as `[abgeleitet]` (derived — unambiguous, worked out directly)
+or `[offen]` (genuinely open-ended/personal, left as a task). Treat
+`[abgeleitet]` answers as reliable but not publisher-verified.
+
+| Abschnitt | Title/Topic | Pages | Relates to Menschen Lektion(en) | Status |
+|---|---|---|---|---|
+| A | [Personen](lesen-schreiben-a1/abschnitt-a.md) | 5–11 | L1, L3, L10 | done |