journal: multi-select emotions and per-category writing templates

- Mood switches from a single enum column to a many-to-many
  JournalEntryMood table so an entry can carry several feelings at
  once; the vocabulary is trimmed to 9 named emotions (dropped the
  overlapping satisfaction scale) with unified noun-style labels.
- Categories can define a content_template that pre-fills the "new
  entry" textarea when selected (only if the user hasn't started
  typing), seeded with a Story/Feelings/Decisions/Insights/Actions
  reflection template on the default "일상" category.
- Fixes a real attribute-injection bug found while building the
  template feature: Jinja's built-in |tojson filter doesn't escape
  double quotes, which breaks a double-quoted x-data="..." attribute
  when the JSON payload contains one; added |forceescape and a
  regression test.

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

app/models/journal.py

@@ -43,6 +43,9 @@ class JournalCategory(Base):
     name: Mapped[str] = mapped_column(String(50), nullable=False)
     color: Mapped[str | None] = mapped_column(String(20), nullable=True)
     sort_order: Mapped[int | None] = mapped_column(Integer, nullable=True)
+    # 이 카테고리로 새 기록을 쓸 때 내용칸에 미리 채워주는 틀(예: Story/Feelings/Decisions/... 회고 양식).
+    # 사용자가 직접 타이핑을 시작하면 더 이상 덮어쓰지 않는다(프론트에서 처리).
+    content_template: Mapped[str | None] = mapped_column(Text, nullable=True)
     created_at: Mapped[datetime] = mapped_column(server_default=func.now(), nullable=False)
 
     entries: Mapped[list["JournalEntry"]] = relationship(