v1.5.0

release: 1.5.0 (#49)

Bump to 1.5.0 (minor, no breaking changes) and turn the pending
changelog into a release entry.

Highlights: addon routes work; CRUD API tokens; scaffold_crud use_seo,
list_template and use_slug; scaffold_seo slug URLs; scaffold_filter
frontend list filter; the npm package no longer ships tests; every
generator scenario runs on a live InstantCMS in CI; knowledge
confidence is enforced; secret columns are masked in DB tools; server
version comes from package.json.

Behaviour changes (no breakage): DB tools mask secret column values
unless include_sensitive is set; get_server_capabilities and
get_project_health report the package version dynamically.