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/29-reflexive-verbs.md

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+# 29. Reflexive Verbs
+
+> Source: [A Complete Guide To Every Fundamental In Spanish (The Conclusion)](https://youtube.com/watch?v=YHDZSHCt1DE&t=7780s)
+
+Reflexive verbs in Spanish are verbs whose action is applied to oneself. A useful way to think of them is that the English equivalent often follows a preposition (wash → wash up, sit → sit down, go → go away). The infinitive ends in **-se** (lavar → lavarse), and a reflexive pronoun (me, te, se, nos, os, se) is placed before the conjugated verb.
+
+## Key Rules
+- Drop **-se** and conjugate the base verb normally; add the matching reflexive pronoun in front.
+- Pronouns: **me, te, se, nos, os, se**.
+- In the present progressive, the pronoun usually goes before *estar* (Te estás lavando), or attached to the gerund (Estás lavándote — accent required).
+- The reflexive form often shifts meaning, mirroring English particle verbs (give vs. give up).
+- Works in every tense; just conjugate the base verb in that tense and keep the pronoun.
+
+## Conjugation / Pattern Tables
+
+### Reflexive pronouns
+| Subject | Pronoun |
+|---|---|
+| yo | me |
+| tú | te |
+| él/ella/usted | se |
+| nosotros | nos |
+| vosotros | os |
+| ellos/ellas/ustedes | se |
+
+### Lavarse — present
+| Subject | Form |
+|---|---|
+| yo | me lavo |
+| tú | te lavas |
+| él/ella | se lava |
+| nosotros | nos lavamos |
+| vosotros | os laváis |
+| ellos | se lavan |
+
+## Examples
+| Spanish | English |
+|---|---|
+| Yo lavo el coche. | I wash the car. |
+| Yo me lavo las manos. | I wash up my hands. |
+| Tú te estás lavando. | You are washing up. |
+| Estás lavándote. | You are washing up. |
+| Él se lavó. | He washed up. |
+| Yo me baño. | I take a bath. |
+| Tú te levantaste. | You got up. |
+| Él se despertó. | He woke up. |
+| Yo me duermo. | I fall asleep. |
+| Yo me voy. | I leave / I go away. |
+| Yo me pongo. | I put (something) on / put down. |
+| Yo me siento. | I sit down. |
+| ¿Cómo te llamas? | What is your name? (lit. How do you call yourself?) |
+| Me llamo Alex. | My name is Alex. |
+
+## Notes & Gotchas
+- Don't say *Me llamo es Alex* or *Yo llamo Alex*; the verb itself contains "call oneself".
+- *Sentarse* is also stem-changing: yo me siento, tú te sientas.
+- *Ponerse* is irregular in yo: yo me pongo.
+- In a present-progressive sentence, attaching the pronoun to the gerund requires a written accent (lavándote, not lavandote).