fix: quote and escape environment variable values

[rgdcastro]

Ensure environment variables containing spaces or special characters are correctly handled in generated .env files by quoting and escaping values.

What is this PR about?

When deploying a service with Docker build type, environment variable values containing spaces (e.g., APP_NAME=This is an awesome app) cause the build to fail with Failed to parse dotenv file. Encountered unexpected whitespace.

This happens because values are written to .env files unquoted, and manually adding quotes in the UI doesn't help since dotenv.parse() strips them before writing.

This PR adds a quoteEnvValue() helper that
wraps values in double quotes with proper escaping of \ and " when generating .env files, applied to both Dockerfile and Docker Compose build paths.

Issues related

Fixes #4137

Greptile Summary

This PR adds a quoteDotenvValue helper that wraps .env values in double quotes with proper \ and " escaping, and applies it to both the Dockerfile and Docker Compose build paths. The fix correctly addresses the whitespace parse error by ensuring values with spaces are quoted before being written to .env files. The escaping order (backslashes before double quotes) is correct, and since prepareEnvironmentVariables runs dotenv.parse() first, any user-supplied quotes are already stripped — so double-quoting is not a concern.

Confidence Score: 5/5

Safe to merge — the fix correctly handles the primary issue and doesn't introduce regressions.

All findings are P2. The one flagged edge case (literal newlines in values producing multi-line entries) requires an unusual combination of circumstances and most parsers handle it fine. The core logic is sound.

No files require special attention.

_{Reviews (1): Last reviewed commit: "fix: quote and escape environment variab..." | Re-trigger Greptile}

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[greptile-apps]

Newline characters not escaped in quoted values

If a value contains an actual newline character (which happens when dotenv.parse() expands a \n escape sequence from a double-quoted entry in the UI), quoteDotenvValue will embed it literally, producing a multi-line entry in the .env file. While many parsers accept this, some stricter Docker tooling may not. Adding \n → \\n (and \r → \\r) escaping would keep every variable on a single line.

Suggested change

	const value = pair.substring(i + 1).replace(/\\/g, "\\\\").replace(/"/g, '\\"');
	const value = pair.substring(i + 1).replace(/\\/g, "\\\\").replace(/"/g, '\\"').replace(/\n/g, "\\n").replace(/\r/g, "\\r");