fix: correct hardcoded folder paths to use underscores

- Fix transcript-extract.sh: `00 Inbox/Clippings` → `00_Inbox/Clippings/`
- Fix firecrawl-batch.sh: `00 Inbox/Clippings` → `00_Inbox/Clippings/`
- Add `-o|--output-dir` flag to firecrawl-batch.sh for custom paths
- Fix update-attachment-links.js: `05 Attachments` → `05_Attachments`
- Fix fix-renamed-links.js: `05 Attachments` → `05_Attachments`
- Fix GEMINI_VISION_QUICK_START.md example paths
- Update README.md with new flag documentation

All folder paths now match actual repo structure (underscores not spaces).
This prevents scripts from failing due to incorrect directory references.

Fixes #9

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

CHANGELOG.md

@@ -12,8 +12,8 @@ and this project adheres to
 
 ### Added
 
-- New `/install-claudesidian-command` for creating shell alias/function to launch
-  vault from anywhere
+- New `/install-claudesidian-command` for creating shell alias/function to
+  launch vault from anywhere
 - iCloud Drive vault detection and import support in `/init-bootstrap` (macOS
   only)
 - Fish shell support for launcher command with proper function syntax