feat(store): SQLite schema, migrations and Danish-aware full-text search

Initial data model for verdande: users, sessions, invites, projects,
sections, tasks, labels, reminders, comments, attachments, activity
and filters, plus personal API tokens.

Search indexes a generated `fold` column alongside the original text.
FTS5's remove_diacritics does not touch ø and æ — Unicode treats them
as letters rather than accented forms — so without it a Danish user
cannot find "grøn" by typing "gron". MatchExpr quotes every term so
free text containing FTS5 operators cannot reach the query planner as
syntax.

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

.gitignore

@@ -0,0 +1,25 @@
+# Build output
+/verdande
+/dist/
+*.exe
+
+# The data volume: database, uploaded files, backups. Never in git.
+/data/
+*.db
+*.db-wal
+*.db-shm
+
+# Frontend
+node_modules/
+/web/.svelte-kit/
+/web/build/
+
+# Local environment
+.env
+.env.local
+
+# Editor / OS
+.DS_Store
+*.swp
+.idea/
+.vscode/