Add vocabulary files for server initialization

Adds three new vocabulary files to the server's vocabulary directory:
`anatomy.txt`, `medications.txt`, and `substances.txt`. A README.md is
also added to explain their purpose, format, and population strategy.
The `server/vocab/raw/` directory is added to `.gitignore`.

.gitignore

@@ -4,3 +4,4 @@ users.toml
 *.snap.new
 repomix-output.xml
 tmpdata/
+server/vocab/raw/

server/vocab/README.md

@@ -0,0 +1,35 @@
+# Gazetteer vocabulary files
+
+These `*.txt` files are loaded once at server startup and used to annotate
+Whisper transcripts with correction hints of the form `Token [?Canonical]`
+before the analysis LLM runs. Design: `~/.claude/plans/happy-mapping-snail.md`.
+
+## File format
+
+- One entry per line, UTF-8, no surrounding whitespace required.
+- Lines that are blank or start with `#` are skipped.
+- Case-insensitive. Duplicates across files are collapsed.
+- No header row, no columns — this is a plain word list.
+
+## Files
+
+| File              | Domain                                | Populated?    |
+| ----------------- | ------------------------------------- | ------------- |
+| `anatomy.txt`     | Latin/Greek anatomical terms          | build script  |
+| `substances.txt`  | Exotic active substances (INNs)       | TBD           |
+| `medications.txt` | Exotic medication brand names         | TBD           |
+
+## Build scripts
+
+The `anatomy.txt` is produced by shell pipeline under `../scripts/`:
+
+```
+./scripts/build-anatomy.sh
+```
+
+It crawls the German Wikipedia "Kategorie:Anatomie", filters the result
+against `hunspell-de-de` to remove everyday German words, and writes the
+remainder here. The result is checked into git — we rebuild only when the
+source vocabulary materially changes, not on every server build.
+
+Intermediate files land under `vocab/raw/`, which is gitignored.

server/vocab/anatomy.txt

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+# Anatomical Latin/Greek terms. Populate via ./scripts/build-anatomy.sh.
+# Blank — mechanism runs as no-op until content is built.

server/vocab/medications.txt

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+# Exotic medication brand names. Population script TBD.
+# Candidate sources: Wikidata (P267 ATC-code joins), Rote Liste alternatives.

server/vocab/substances.txt

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+# Exotic active substances (INN names). Population script TBD.
+# Candidate source: WHO ATC classification (free, tabular).