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/notes/40-past-perfect-tense.md

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+# 40. Past Perfect Tense
+
+> Source: [A Complete Guide To Every Fundamental In Spanish (The Conclusion)](https://youtube.com/watch?v=YHDZSHCt1DE&t=11170s)
+
+The past perfect (`pluscuamperfecto`) talks about what someone **had** done before another past action. It uses the imperfect of `haber` + a past participle.
+
+## Key Rules
+- Formula: **imperfect `haber`** (`había, habías, había, habíamos, habíais, habían`) + **past participle**.
+- Often pairs with `ya` (already), placed *before* `haber`: `Ella ya había salido`.
+- Often pairs with `antes de` + noun/infinitive (= "before"): `Antes de llegar a la escuela, yo ya había comido`.
+- Like the present perfect, `haber + participle` is inseparable; negatives, DOPs, IOPs, and reflexive pronouns go before `haber`.
+- Spanish has three "had"s in English: preterite (`tuve`), imperfect (`tenía`), past perfect (`había tenido`).
+
+## Conjugation / Pattern Tables
+
+### `haber` (imperfect)
+| Pronoun | Form |
+|---|---|
+| yo | había |
+| tú | habías |
+| él/ella | había |
+| nosotros | habíamos |
+| vosotros | habíais |
+| ellos | habían |
+
+## Examples
+| Spanish | English |
+|---|---|
+| Ella ya había salido. | She had already left. |
+| Yo ya había estudiado. | I had already studied. |
+| Antes de llegar a la escuela, yo ya había comido. | Before arriving at school, I had already eaten. |
+| Antes de este mes, yo había trabajado mucho. | Before this month, I had worked a lot. |
+| Él me lo había mostrado. | He had shown it to me. |
+| Él nunca me lo había mostrado. | He had never shown it to me. |
+| Él no me lo había mostrado. | He had not shown it to me. |
+| Antes de ir al trabajo, me había duchado. | Before going to work, I had taken a shower. |
+| Yo había comido antes de la fiesta. | I had eaten before the party. |
+| Nosotros habíamos visto la película. | We had seen the movie. |
+
+## Notes & Gotchas
+- Same inseparability rule as the present perfect.
+- "I had a dog" (state in the past) = `Yo tenía un perro` (imperfect of `tener`), not the past perfect.
+- "I had to study" (obligation) = `Yo tuve que estudiar` (preterite of `tener`).
+- "I had eaten" (action before another past action) = `Yo había comido` (past perfect).
+- Conversationally, the simple past is often used instead of the past perfect.