feat(core): dynamic custom frontmatter fields for CTF writeup metadata

- Add extra_fields JSONB column to documents table (migration 0003)
- CreateDocInput/UpdateDocInput: extraFields?: Record<string, string>
- parseFile: extracts non-standard frontmatter keys as extraFields
- stringifyFile: writes extraFields dynamically to YAML frontmatter
- toMeta: spreads extraFields from DB row into DocumentMeta
- DocForm: '+ Add field' UI for content creators to add any metadata
- API routes: splitPayload() separates standard vs custom fields
- Doc page: CustomFieldBadges dynamically renders any custom field
- Add db:migrate / db:push scripts + deploy workflow migration step
- Add CTF writeup template (content/writeups/ctf/template/)
- Add sample DEF CON writeup with event/challenge/category/difficulty/points
- Add @tailwindcss/typography for table rendering (prose classes)
- Add remark-gfm for GitHub Flavored Markdown table parsing

.github/workflows/deploy.yml

@@ -47,6 +47,7 @@ jobs:
             git pull origin main
             /home/code/.bun/bin/bun install --frozen-lockfile
             /home/code/.bun/bin/bun --cwd apps/web run build
+            /home/code/.bun/bin/bun --cwd packages/db run db:migrate
             sudo systemctl restart mcpedia-web mcpedia-api mcpedia-mcp mcpedia-worker
             sleep 3
             systemctl --no-pager status mcpedia-web mcpedia-api mcpedia-mcp mcpedia-worker --no-legend