docs: create GEMASTIK 2026 Warmup writeups (ch1-14) via MCP DB API

- Deleted all 14 dummy docs from DB + filesystem
- Created 14 Gemastik warmup writeups + index via create_document API (DB-first)
- ch1-ch12: encoding/stego/web/pwn basics
- ch13: RSA small factors
- ch14: RSA special integers via paper-search (GCD with paper appendix primes)
- All 15 docs indexed and live at wiki.asepharyana.my.id

content/writeups/gemastik-2026-warmup/ch12-layers.md

@@ -1,13 +1,20 @@
 ---
 title: "Layers — Hex to Base64 Chain"
+type: "writeup"
+section: "writeups"
+status: "published"
+author: "asep"
+tags: ["gemastik", "ctf", "warmup", "crypto"]
+path: "writeups/gemastik-2026-warmup/ch12-layers.md"
+created_at: "2026-08-21T07:25:48.559Z"
+updated_at: "2026-08-21T07:25:48.559Z"
 event: "GEMASTIK 2026 Warmup"
-challenge: "Layers"
+challenge: "Layers — Hex to Base64 Chain"
 category: "crypto"
 points: 500
 difficulty: "easy"
 flag: "GEMASTIK19{h3x_lQlu_b4s3_ch41n}"
 ---
-
 # Layers (500 pts) — Encoding chain
 
 **File:** `chall.txt` → `5230564e51564e55535573784f58746f4d33686662464673645639694e484d7a58324e6f4e44467566513d3d`
@@ -31,4 +38,4 @@ print(flag)
 
 ## Flag
 
-`GEMASTIK19{h3x_lQlu_b4s3_ch41n}`
+`GEMASTIK19{h3x_lQlu_b4s3_ch41n}`