refactor: rename project from Freepik to Magnific

Rename all identifiers, strings, file names, env vars, CLI entry point,
ASCII banner, and API endpoint to reflect the company rebrand.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

pyproject.toml

@@ -3,9 +3,9 @@ requires = ["hatchling"]
 build-backend = "hatchling.build"
 
 [project]
-name = "freepik-cli"
+name = "magnific-cli"
 version = "0.1.0"
-description = "A beautiful CLI for the Freepik AI API — generate images, videos, and more"
+description = "A beautiful CLI for the Magnific AI API — generate images, videos, and more"
 readme = "README.md"
 requires-python = ">=3.11"
 license = { text = "MIT" }
@@ -30,10 +30,10 @@ dev = [
 ]
 
 [project.scripts]
-freepik = "freepik_cli.main:app"
+magnific = "magnific_cli.main:app"
 
 [tool.hatch.build.targets.wheel]
-packages = ["freepik_cli"]
+packages = ["magnific_cli"]
 
 [tool.ruff]
 line-length = 100