Add an Input File Source operator that reads file paths from input tuples

[aglinxinyuan]

Feature Summary

Add a new Input File Source operator that accepts file path strings from upstream tuples and scans the referenced files.

This would allow workflows to construct file paths dynamically and pass them into a file source operator, instead of requiring file selection through the property panel.

Proposed Solution or Design

Introduce a new source operator named Input File Source.

The operator should accept file paths from an input port and use those paths as its source input at execution time. This makes it possible to connect upstream operators that produce file path strings to downstream file scanning logic.

At a high level:

• Add a dedicated input-based file source operator instead of overloading the existing file selector operator.
• The operator should read file path strings from upstream tuples.
• The operator should resolve those paths using Texera’s existing file resolution logic.
• The operator should be directly usable in workflows where file paths are generated dynamically.
• Add the operator registration and icon so it appears as a first-class operator in the workflow editor.

Impact / Priority

(P2)Medium – useful enhancement

Affected Area

No response