feat: add env-bridge tool for containerized Symfony env loading

[Soner (shyim)]

Summary

• Extract LoadSymfonyEnvFile from internal/extension into a dedicated internal/envfile package for better separation of concerns
• Add standalone env-bridge binary that loads Symfony .env files before executing a given command, useful for containerized/Docker workflows
• Add GitHub Actions workflow to build and publish env-bridge Docker image to GHCR

Test plan

• Verify go build ./... succeeds
• Verify existing commands using LoadSymfonyEnvFile (admin-watch, storefront-watch, dump) still work
• Test env-bridge binary loads env files correctly
• Verify Docker build from Dockerfile.env-bridge produces a working image

[Copilot]

Pull request overview

This PR extracts Symfony .env loading into a dedicated internal/envfile package, introduces an env-bridge wrapper binary to preload env vars before executing a command (aimed at container/Docker workflows), and adds CI to build/publish an env-bridge Docker image to GHCR.

Changes:

• Moved LoadSymfonyEnvFile out of internal/extension into new internal/envfile package and updated callers.
• Added env-bridge binary to load Symfony env files from the working directory and exec a provided command.
• Added Dockerfile.env-bridge and a GitHub Actions workflow to build/push an env-bridge image.

Reviewed changes

Copilot reviewed 8 out of 9 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
internal/extension/util.go	Removes Symfony env loading from the extension util package.
internal/envfile/envfile.go	New shared package implementing Symfony .env loading logic.
env-bridge/main.go	New wrapper CLI that loads env files then executes a command.
cmd/project/project_storefront_watch.go	Switches storefront watch to use internal/envfile.
cmd/project/project_dump.go	Switches dump command env loading to internal/envfile.
cmd/project/project_admin_watch.go	Switches admin watch to use internal/envfile.
Dockerfile.env-bridge	Adds multi-stage build for a minimal env-bridge container image.
.gitignore	Ignores a locally built env-bridge binary output.
.github/workflows/env-bridge-docker.yml	Adds workflow to build/push env-bridge image to GHCR.

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