file: validate output path for OS-specific invalid characters

[twmb]

Override the benthos file output with a connect-local implementation that rejects characters causing silent data loss: colons on macOS (HFS+/APFS maps ':' to '/'), and <, >, :, ", |, ?, * plus control characters on Windows. NUL bytes are rejected on all platforms.

Fixes #1005.

[claude]

Claude finished @twmb's task in 4m 40s —— View job

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Commits

LGTM

Review

Clean implementation that overrides the benthos file output to add OS-specific path validation. Registration pattern, field name constants, config parsing, mutex usage, and test structure all follow project conventions. One minor pattern violation found.

1. Error wrap prefix at output_file.go#L187 uses "path interpolation error: %w" instead of gerund form ("interpolating path: %w") per godev.md.

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[mmatczuk]

Reminds me of https://github.com/saucelabs/forwarder/blob/main/fileurl/fileurl.go

[claude]

Commits
LGTM

Review
Override of the benthos file output to reject characters that cause silent data loss on Windows/macOS/all platforms. The new validateFilePath logic is well-covered by a table-driven unit test across platforms.

LGTM