[FEATURE] Add syntax highlighting for 1C:Enterprise (BSL) language

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

1C:Enterprise platform, which uses BSL language. Currently, the code appears as plain text.

Additional context

• Language Name: 1C:Enterprise / BSL
• Common Extensions: .bsl, .os (OneScript)

Proposed Solution

BSL is already supported by major syntax highlighting engines including PrismJS, Shiki, and Pygments, so integration should be straightforward.

Alternative Solutions

_No response_

Priority

Medium - Would be very helpful

Feature Category

CLI commands and flags

Use Case Example

_No response_

Additional Context

_No response_