Add 13 new grammar notes with 1010 exercises from video extraction

Scraped a 4h Spanish fundamentals YouTube video (transcript + OCR on
14810 frames), extracted structured content across 52 chapters, and
generated fill-in-the-blank quizzes for every grammar topic.

- 13 new GrammarNote entries (articles, possessives, demonstratives,
  greetings, poder, al/del, prepositional pronouns, irregular yo,
  stem-changing, stressed possessives, present/future perfect, present
  indicative conjugation)
- 1010 generated exercises across all 36 grammar notes (new + existing)
- Fix tense guide parser to handle unnumbered *Usages* blocks
- Rewrite 6 broken tense guide bodies (imperative, subj pluperfect,
  subj future) with numbered usage format
- Bump courseDataVersion 5→6 with TenseGuide refresh on upgrade
- Add docs/spanish-fundamentals/ with raw transcripts, polished notes,
  structured JSON, and exercise data

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docs/spanish-fundamentals/exercises/seed/saber-vs-conocer.json

@@ -0,0 +1,98 @@
+[
+  {
+    "sentence": "Yo _____ la respuesta a la pregunta.",
+    "correct": "sé",
+    "distractor": "conozco",
+    "explanation": "Knowing a fact uses saber; yo form is sé (with accent).",
+    "source_chapter": "23",
+    "source_title": "The Verb Saber"
+  },
+  {
+    "sentence": "Tú _____ tocar la guitarra muy bien.",
+    "correct": "sabes",
+    "distractor": "conoces",
+    "explanation": "Knowing how to do something is a skill — use saber.",
+    "source_chapter": "23",
+    "source_title": "The Verb Saber"
+  },
+  {
+    "sentence": "Yo _____ hablar tres idiomas.",
+    "correct": "sé",
+    "distractor": "se",
+    "explanation": "Yo sé needs the accent; without it, 'se' is a reflexive pronoun.",
+    "source_chapter": "23",
+    "source_title": "The Verb Saber"
+  },
+  {
+    "sentence": "Nosotros _____ la verdad sobre eso.",
+    "correct": "sabemos",
+    "distractor": "conocemos",
+    "explanation": "The truth is a fact — use saber.",
+    "source_chapter": "23",
+    "source_title": "The Verb Saber"
+  },
+  {
+    "sentence": "Ella _____ cocinar comida italiana.",
+    "correct": "sabe",
+    "distractor": "conoce",
+    "explanation": "Cooking is a skill (how to do something) — use saber.",
+    "source_chapter": "23",
+    "source_title": "The Verb Saber"
+  },
+  {
+    "sentence": "Ellos _____ qué hora es.",
+    "correct": "saben",
+    "distractor": "conocen",
+    "explanation": "Time is factual information — use saber.",
+    "source_chapter": "23",
+    "source_title": "The Verb Saber"
+  },
+  {
+    "sentence": "Yo _____ a María desde la escuela.",
+    "correct": "conozco",
+    "distractor": "sé",
+    "explanation": "Knowing a person uses conocer (with personal 'a'). Yo form is conozco.",
+    "source_chapter": "24",
+    "source_title": "The Verb Conocer"
+  },
+  {
+    "sentence": "¿Tú _____ Madrid?",
+    "correct": "conoces",
+    "distractor": "sabes",
+    "explanation": "Knowing a place uses conocer.",
+    "source_chapter": "24",
+    "source_title": "The Verb Conocer"
+  },
+  {
+    "sentence": "Nosotros _____ esta canción.",
+    "correct": "conocemos",
+    "distractor": "sabemos",
+    "explanation": "Being familiar with a thing uses conocer.",
+    "source_chapter": "24",
+    "source_title": "The Verb Conocer"
+  },
+  {
+    "sentence": "Ellos _____ a mis padres.",
+    "correct": "conocen",
+    "distractor": "saben",
+    "explanation": "Knowing people uses conocer with personal a.",
+    "source_chapter": "24",
+    "source_title": "The Verb Conocer"
+  },
+  {
+    "sentence": "Ella _____ que tú vienes mañana.",
+    "correct": "sabe",
+    "distractor": "conoce",
+    "explanation": "A fact (that you're coming) uses saber, not conocer.",
+    "source_chapter": "24",
+    "source_title": "The Verb Conocer"
+  },
+  {
+    "sentence": "Yo _____ ese restaurante; está cerca.",
+    "correct": "conozco",
+    "distractor": "sé",
+    "explanation": "Familiarity with a place uses conocer.",
+    "source_chapter": "24",
+    "source_title": "The Verb Conocer"
+  }
+]