Enhancement/added import command lock flag

[dm-vasylenko]

Please make sure these boxes are checked before submitting your PR - thank you!

• Pull request is based against main branch
• README.md reflects changes (if applicable)
• New files contain a license header

Proposed changes

Added --lock-config (-c) option to the config:data:import CLI command. When used, imported configuration values are written to both the database (core_config_data) and app/etc/config.php, making them
read-only (greyed out) in Admin > Stores > Configuration.

Changed files

Command/ImportCommand.php

• Added --lock-config (-c) option definition in configure()

Model/Processor/ImportProcessor.php

• Added 3 constructor dependencies: DeploymentConfig\Writer, ConfigPathResolver, ArrayManager
• During the import loop, values are collected into a $lockData array when --lock-config is active
• After the loop, all collected values are batch-written to app/etc/config.php in a single saveConfig() call (merge mode)
• !!DELETE entries print a notice that locked values in config.php must be removed manually
• !!KEEP entries are unaffected (skipped as before)

README.md / docs/config-import.md

• Documented the new --lock-config option with usage examples and caveats

Usage

Standard import (unchanged)

php bin/magento config:data:import config/store production

Import + lock in config.php

php bin/magento config:data:import config/store production --lock-config

...

This PR adds an additional --lock-config option to the import command. Issue #24

[therouv]

Thank you, @dm-vasylenko ! Looks good.
Will fix the CS issues and merge it manually tomorrow :)