feat: add variable import/export commands

[manwindersingh1712]

Description

Adds bulk import/export functionality for environment variables, enabling easier CI/CD integration, backups, and bulk configuration management.

New Commands

railway variable import

Import environment variables from a .env or .json file.

# Import from .env file (auto-detected)
railway variable import --file .env.staging

# Import from JSON file
railway variable import --file backup.json

# Import to specific service/environment
railway variable import --file .env --service <my-service> --environment <production/staging/etc>

# Auto-accept all overwrites (non-interactive/CI mode)
railway variable import --file .env --yes

# Import without triggering deployments
railway variable import --file .env --skip-deploys

# JSON output
railway variable import --file .env --json

Features:

• Auto-detects format by file extension (.json vs .env)
• Interactive conflict resolution (prompts with [y/N/q] for existing keys)
• Non-TTY mode skips conflicts with warning (use --yes to override)
• Supports quoted values, escape sequences (\n, \t, \r, \"), comments, and empty lines

railway variable export

Export environment variables to a .env or .json file.

# Export to .env file
railway variable export --file .env.backup

# Export to JSON file
railway variable export --file backup.json

# Export from specific service/environment
railway variable export --file prod.env --service my-service --environment production

# JSON output to stdout
railway variable export --file backup.env --json

Features:

• Auto-detects format by file extension
• Properly escapes special characters for .env format
• Pretty-printed JSON output

Supported File Formats

.env Format

# Basic key-value pairs
DATABASE_URL=postgres://localhost/mydb
API_KEY=secret123

# Double-quoted values with escape sequences
JSON_DATA="{\"key\": \"value\"}"
MULTILINE="line1\nline2\ttab"

# Single-quoted values (no escape processing)
LITERAL='no $pecial \processing'

# Empty values
EMPTY=

# Comments and empty lines are ignored
# This is a comment

JSON Format

{
  "DATABASE_URL": "postgres://localhost/mydb",
  "API_KEY": "secret123",
  "DEBUG": "true"
}

CI/CD Usage Example

# Export production variables for backup
railway variable export --file prod-backup.json --environment production

# Import variables to staging (non-interactive)
railway variable import --file prod-backup.json --environment staging --yes

# Or use --skip-deploys to set variables without triggering deploys
railway variable import --file .env.ci --yes --skip-deploys

Testing

All tests pass:

• 9 CLI parsing tests for import/export commands
• 18 unit tests for .env and JSON parsers
• 135 total tests

cargo test