feat: implement template compression and view count filtering

- Add gzip compression for workflow JSONs (89% size reduction)
- Filter templates with ≤10 views to remove low-quality content
- Reduce template count from 4,505 to 2,596 high-quality templates
- Compress template data from ~75MB to 12.10MB
- Total database reduced from 117MB to 48MB
- Add on-the-fly decompression for template retrieval
- Update schema to support compressed workflow storage

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

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

src/database/schema.sql

@@ -35,7 +35,8 @@ CREATE TABLE IF NOT EXISTS templates (
   author_username TEXT,
   author_verified INTEGER DEFAULT 0,
   nodes_used TEXT, -- JSON array of node types
-  workflow_json TEXT NOT NULL, -- Complete workflow JSON
+  workflow_json TEXT, -- Complete workflow JSON (deprecated, use workflow_json_compressed)
+  workflow_json_compressed TEXT, -- Compressed workflow JSON (base64 encoded gzip)
   categories TEXT, -- JSON array of categories
   views INTEGER DEFAULT 0,
   created_at DATETIME,