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

packages/core/src/index.service.ts

@@ -48,6 +48,7 @@ export async function indexContentFile(
       tags: meta.tags,
       path: meta.path,
       body,
+      extraFields: meta.extraFields ?? {},
       createdAt: new Date(meta.createdAt || nowIso),
       updatedAt: new Date(nowIso),
     })
@@ -62,6 +63,7 @@ export async function indexContentFile(
         tags: meta.tags,
         path: meta.path,
         body,
+        extraFields: meta.extraFields ?? {},
         updatedAt: new Date(nowIso),
       },
     });