Update hunspell filter to use min token length

The `filter-hunspell-de.sh` script now uses a `MIN_LEN` variable that is
synchronized with the `MIN_TOKEN_LEN` constant in
`src/gazetteer/mod.rs`.
This ensures that short tokens, which are prone to false positives due
to
collisions with common German words, are filtered out by both the
gazetteer
loading and the Hunspell dictionary processing.

Additionally, the script's dependency instructions have been updated to
be
more comprehensive, listing package manager commands for Arch/CachyOS,
Debian/Ubuntu, and Fedora. The `awk` command has been introduced to
filter
out tokens shorter than `MIN_LEN` before sorting and deduplicating.

The `Gazetteer::insert` method has been updated to skip entries shorter
than `MIN_TOKEN_LEN` to prevent noisy phonetic collisions. The
`best_candidate`
helper function has been extracted to improve readability and structure.
The test cases have been updated to reflect the change in
`MIN_TOKEN_LEN`
from 4 to 5 and to use more relevant examples for the updated
functionality,
such as "Cerebrum" and "Zerebrum". The `anatomy.txt` file has been
updated
to reflect that anatomical terms are currently disabled. The
`medications.txt` file has been significantly expanded with a curated
list
of German medication brand and active ingredient names.

server/vocab/anatomy.txt

@@ -1,2 +1,3 @@
-# Anatomical Latin/Greek terms. Populate via ./scripts/build-anatomy.sh.
-# Blank — mechanism runs as no-op until content is built.
+# Anatomical Latin/Greek terms — currently disabled.
+# Scope narrowed to medications. If re-enabling, populate via
+# ./scripts/build-anatomy.sh and expect eponym-beifang.

server/vocab/medications.txt

@@ -1,2 +1,165 @@
-# Exotic medication brand names. Population script TBD.
-# Candidate sources: Wikidata (P267 ATC-code joins), Rote Liste alternatives.
+# Seed list of German medication brand names + commonly dictated
+# active-ingredient names. Roughly aligned with the AOK Arzneiverordnungs-
+# Report top-prescribed set. Curated, not crawled — new entries should
+# be ≥5 chars (phonetic-collision safety) and phonetically distinctive.
+# Maintain alphabetical order, one entry per line, no inline comments.
+Adalat
+Aldactone
+Allopurinol
+Amiodaron
+Amlodipin
+Amoxicillin
+Arcoxia
+Aspirin
+Atacand
+Atorvastatin
+Azithromycin
+Beloc
+Benazepril
+Berodual
+Betahistin
+Bisoprolol
+Budesonid
+Buscopan
+Candesartan
+Carvedilol
+Cefuroxim
+Celebrex
+Cetirizin
+Ciprofloxacin
+Citalopram
+Clarithromycin
+Clexane
+Clindamycin
+Clopidogrel
+Concor
+Cortison
+Dabigatran
+Dexamethason
+Diazepam
+Diclofenac
+Digoxin
+Diltiazem
+Dimenhydrinat
+Dobendan
+Dolormin
+Doxycyclin
+Duloxetin
+Edoxaban
+Eliquis
+Enalapril
+Erythromycin
+Escitalopram
+Esomeprazol
+Euthyrox
+Fluoxetin
+Foradil
+Forxiga
+Furosemid
+Gabapentin
+Glucophage
+Haldol
+Heparin
+Humira
+Ibuprofen
+Iberogast
+Imodium
+Insulin
+Isoptin
+Januvia
+Jardiance
+Ketamin
+Keppra
+Klacid
+Lactulose
+Lansoprazol
+Lantus
+Lasix
+Laxoberal
+Lisinopril
+Lixiana
+Lorazepam
+Lorzaar
+Lovastatin
+Macrogol
+Marcumar
+Mesalazin
+Metformin
+Methotrexat
+Metoprolol
+Metronidazol
+Mirtazapin
+Morphium
+Movicol
+Mucofalk
+Naproxen
+Nasivin
+Nebivolol
+Nexium
+Nitrolingual
+Norvasc
+Novalgin
+Novorapid
+Olanzapin
+Olynth
+Omeprazol
+Otriven
+Oxazepam
+Oxycodon
+Ozempic
+Pantoprazol
+Paracetamol
+Penicillin
+Perenterol
+Phenprocoumon
+Pradaxa
+Pravastatin
+Prednisolon
+Prednison
+Pregabalin
+Pulmicort
+Quetiapin
+Ramipril
+Ranitidin
+Rhinospray
+Risperidon
+Rivaroxaban
+Rosuvastatin
+Salbutamol
+Sertralin
+Sildenafil
+Simvastatin
+Sinupret
+Sirdalud
+Spiriva
+Spironolacton
+Stilnox
+Sumatriptan
+Symbicort
+Tadalafil
+Tavor
+Telmisartan
+Temesta
+Thyroxin
+Timolol
+Torasemid
+Tramadol
+Tranxilium
+Trulicity
+Ultracain
+Valsartan
+Venlafaxin
+Ventolin
+Verapamil
+Viagra
+Viani
+Victoza
+Voltaren
+Voluven
+Vomex
+Warfarin
+Xarelto
+Ximovan
+Zolpidem
+Zopiclon
+Zyprexa