chore: remove marketing files from repository

Marketing materials kept locally but excluded from git.
Files moved to .gitignore for local use only.

Author: MacroMan5

.gitignore

@@ -91,6 +91,14 @@ site/
 # NOTES.md
 # TODO-personal.md
 
+# Marketing and strategy files (keep local only)
+MARKETING_STRATEGY.md
+SOCIAL_MEDIA_TEMPLATES.md
+QUICK_START_MARKETING.md
+GITHUB_TOPICS.txt
+*_MARKETING*.md
+*_STRATEGY*.md
+
 # Flow and error files from debugging (these should not be committed)
 flow.json
 erreur.json