Preview branch migration runner corrupts newlines to literal 'n' characters

- [x] I confirm this is a bug with Supabase, not with my own application. - [x] I confirm I have searched the [Docs](https://docs.supabase.com), GitHub [Discussions](https://github.com/supabase/supabase/discussions), and [Discord](https://discord.supabase.com). ## Bug report ### Describe the bug When Supabase preview branches run migrations, newline characters (`\n` / `0x0a`) in SQL migration files are being converted to the literal character `n`, causing syntax errors. The migration file on disk has correct Unix line endings (verified via hex dump), but the preview branch migration runner corrupts them before executing. ### To Reproduce 1. Have a migration file with multi-line SQL statements (e.g., `CREATE TYPE ... AS ENUM` with values on separate lines) 2. Push a branch that triggers a preview branch creation 3. The preview branch migration runner fails with a syntax error ### Expected behavior Migration files should be executed with their original newline characters preserved. ### Actual behavior Newlines are stripped and replaced with the literal character `n`. For example, this valid SQL: ```sql create type subscription_status as ENUM ( 'active', 'trialing', 'past_due' ); ``` Gets executed as: ```sql create type subscription_status as ENUM (n 'active',n 'trialing',n 'past_due'n); ``` Resulting in: ``` ERROR: syntax error at or near "n" (SQLSTATE 42601) ``` ### Screenshots / logs From the preview branch workflow logs: ``` 2026/02/09 13:55:39 ERROR: syntax error at or near "n" (SQLSTATE 42601) At statement: 0 create type subscription_status as ENUM (n 'active',n 'trialing',n 'past_due',n 'canceled',n 'unpaid',n 'incomplete',n 'incomplete_expired',n 'paused'n) ^ ``` ### Hex dump of migration file (proving correct line endings) ``` 00000020: 6173 2045 4e55 4d28 0a20 2027 6163 7469 as ENUM(. 'acti 00000030: 7665 272c 0a20 2027 7472 6961 6c69 6e67 ve',. 'trialing ``` `0a` = proper LF newline. The file is f…