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/44-conditional-perfect-tense.md

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+# 44. Conditional Perfect Tense
+
+> Source: [YouTube](https://youtube.com/watch?v=YHDZSHCt1DE&t=12051s)
+
+The conditional perfect describes what *would have* happened or what one *would have* done. It's formed with the conditional of `haber` + a past participle.
+
+## Key Rules
+- Form: **conditional of `haber` + past participle**.
+- Endings of `haber` follow the regular conditional pattern (`-ía, -ías, -ía, -íamos, -íais, -ían`).
+- Past participle does **not** change to agree with subject (it's part of a compound verb).
+- Common use: an action that **would have happened but didn't**.
+- Pairs with the pluperfect subjunctive in contrary-to-fact `si` clauses: *Si hubiera estudiado, habría aprobado.*
+
+## Conjugation / Pattern Tables
+
+### `haber` (conditional) + participle
+| Pronoun | haber | example |
+|---|---|---|
+| yo | habría | habría terminado |
+| tú | habrías | habrías comido |
+| él/ella | habría | habría abierto |
+| nosotros | habríamos | habríamos vivido |
+| vosotros | habríais | habríais hecho |
+| ellos | habrían | habrían dicho |
+
+## Examples
+| Spanish | English |
+|---|---|
+| Yo habría terminado mi trabajo. | I would have finished my work. |
+| Tú habrías disfrutado estar ahí. | You would have enjoyed being there. |
+| Ella habría abierto las ventanas. | She would have opened the windows. |
+| Nosotros habríamos comido más. | We would have eaten more. |
+| Ellos habrían venido a la fiesta. | They would have come to the party. |
+| Yo habría dicho la verdad. | I would have told the truth. |
+| ¿Habrías hecho lo mismo? | Would you have done the same? |
+
+## Notes & Gotchas
+- Don't confuse `habría` (conditional perfect) with `había` (pluperfect indicative) or `habría` vs. `habrá` (future perfect).
+- Irregular participles still apply: `abierto`, `dicho`, `hecho`, `escrito`, `puesto`, `visto`, `vuelto`, `roto`, `muerto`.
+- Rare in spoken Spanish — recognize it but don't worry about over-using it.