feat(decks): many more lessons in every language, one file per theme #30

Problem

Several themes in the panel have almost nothing to practice. For a pt-BR speaker learning English at B2: telefone 3 items, saúde 4, emergência 5, social 8, compras 13. Spanish is the same or thinner. Ticking one of those themes repeats the same few phrases. Portuguese for English speakers has first words only. The curated decks are one long file per language, hard to find a theme in.

Approach

• More real-life lessons for the themes that already exist, in every language we ship, the same situations in each.
• Each with the three answers (short / complete / polished), a level from A1 to B1, accepted variants and a tip where a false friend or a pronunciation trap is likely.
• Spanish for English speakers: every new Spanish phrase gets its entry in the overlay.
• Portuguese for English speakers: full phrases too, not only first words.
• Fill the rungs still open in LADDER_GAPS; add home and bank, getting around, and everyday slang that people really use.
• Curated decks become one folder per language with one file per theme, file names in English.

Checklist

• telefone, saúde, emergência, social, compras have 16+ items each in English and Spanish
• Every new phrase has a polished answer; short <= complete <= polished in words
• No new phrase repeats one already in the curated, basics or Lexicaster decks
• Every core topic climbs pre-A1 to B1 in both pt-BR decks (LADDER_GAPS empty)
• Spanish overlay for English speakers stays complete
• Portuguese for English speakers has full phrases and general tips; its first-steps file stays words and chunks
• Slang: everyday, mild, not tied to one city
• One folder per language, one file per theme; decks identical before and after the split
• All text passes font::supports
• Reviewed by a native Spanish speaker
• CI run on the branch