v0.4.0 — blueprint-only declarations + ecommerce flagship (BREAKING)

The blueprint becomes GoFastr's single declaration format: the legacy
entities/*.json path is removed (BREAKING), and a declaration-driven
flagship (examples/ecommerce) proves one gofastr.yml → SQL + REST + OpenAPI

• MCP + UI end to end.

Added

• Declaration-driven flagship example — examples/ecommerce. A complete
  storefront (five related entities, screens, nav, custom endpoints, seed data,
  and a theme) declared once in gofastr.yml and emitted as runnable Go by
  gofastr generate --from=gofastr.yml (the generated gen/ is gitignored).
  flagship_test.go regenerates, builds, and runs it to prove every surface —
  SQL schema, REST CRUD, OpenAPI, the 25-tool MCP surface, and the
  server-rendered UI — is live with zero hand-written application code. See
  examples/ecommerce/BUILD_JOURNAL.md.

Fixed

• gofastr generate now gofmt's its generated Go. Blueprint output is run
  through go/format before being written, so the emitted package is clean and
  stable across regenerations (no more spurious diffs on re-generate).
• gofastr generate --from re-run no longer refuses to clean main.go. The
  output-dir cleaner now owns main.go (the blueprint emits gen/main.go), so
  regenerating over an existing gen/ succeeds instead of erroring with
  "refusing to clean — contains unknown entry".

Removed

• BREAKING: the legacy entities/*.json declaration format is gone. The
  gofastr.yml blueprint is now the single declaration format — it decodes into
  the same EntityDeclaration shape and additionally emits main.go, screens,
  and stubs, so the JSON-file path was a strict subset. Removed:

  • Framework API: App.EntityFromFile, App.EntitiesFromDir,
    App.GroupEntitiesFromDir, framework.LoadEntityDeclaration,
    framework.LoadEntityDeclarations. (The EntityDeclaration /
    FieldDeclaration types and .Config() remain — they are the in-memory
    shape the blueprint loader decodes entities into.)
  • CLI: gofastr generate entity <name> and gofastr new entity <name> (both
    now print a removal notice and exit non-zero); the --entities=<dir> flag
    on gofastr generate, gofastr migrate generate, and gofastr migrate diff.
  • gofastr generate no longer defaults to "scan entities/ and generate." It
    requires --from=<blueprint.yml> (or a gofastr.codegen.yml extension
    config). Auto-discovery of gofastr.yml is intentionally not done — that
    filename is also the gofastr init isolation config.

  Migration: declare entities in a gofastr.yml blueprint and run
  gofastr generate --from=gofastr.yml, or declare them in Go via
  app.Entity(name, framework.EntityConfig{…}) (unchanged). gofastr migrate generate <name> --from=<blueprint.yml> and gofastr migrate diff --from=<blueprint.yml> replace the old --entities=<dir> form. The
  gofastr.codegen.yml extension protocol and codegen package are unchanged.

  Follow-up (kiln is experimental): kiln freeze still writes
  entities/*.json as its own snapshot artifact; emitting a gofastr.yml
  blueprint directly is tracked for a later pass.