journal: paste image from clipboard, cap embedded image size, fix media persistence

- Paste-to-embed: pasting an image into the markdown editor uploads it and
  inserts ![](url) at the cursor. Unlike gallery attachments these aren't
  tied to a journal_entry (the entry may not exist yet while composing), so
  they're stored per-user under app/media/journal/{user_id}/pasted/ with no
  DB row, served through an ownership-scoped route, and never cleaned up
  automatically when an entry is deleted -- an accepted tradeoff at this
  app's personal scale.
- The markdown sanitizer was stripping all <img> tags (not on the bleach
  allowlist), which would have silently deleted every pasted image on save;
  added img/src/alt/title while keeping event-handler attributes blocked.
- Cap embedded image width in both the editor pane and the rendered preview
  so a large pasted photo can't overflow its card.
- Fix real data loss risk found while testing this: docker-compose.yml had
  no volume for app/media, so every container recreate during a deploy wiped
  uploaded photos, and deploy_sftp.py was syncing app/media/ (runtime user
  data, not source) into the remote build context. Added the volume mount
  and excluded media/ from the sync script. Recovered and relocated the
  real attachments that had already landed in the wrong place on the NAS
  during earlier deploys this session.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

scripts/deploy_sftp.py

@@ -23,7 +23,9 @@ DEPLOY_ENV_PATH = PROJECT_ROOT / "deploy.env"
 
 # Dockerfile이 COPY하는 것과 동일한 목록 + 컨테이너 정의 파일
 SYNC_TARGETS = ["pyproject.toml", "alembic.ini", "Dockerfile", "docker-compose.yml", "app", "migrations", "scripts"]
-SKIP_NAMES = {"__pycache__"}
+# app/media는 소스 코드가 아니라 런타임에 생성되는 유저 업로드 데이터라 절대 동기화하면 안 된다 —
+# 로컬에서 테스트하며 쌓인 실제 유저 사진이 원격 빌드 컨텍스트로 그대로 올라가버리는 사고가 있었다.
+SKIP_NAMES = {"__pycache__", "media"}
 SKIP_SUFFIXES = {".pyc"}