Add Python UDF UI parameter support

[carloea2]

Task Summary

Add support for Python UDF authors to declare UI-editable parameters directly in their UDF code using self.UiParameter(...).

Today, users who want configurable Python UDF behavior usually need to hard-code values in the Python editor or manually manage operator properties. This feature lets the Python code declare the expected parameters, while the Texera UI provides input fields for the values.

Example user code:

from pytexera import *
from typing import Iterator, Optional

class ProcessTupleOperator(UDFOperatorV2):

    @overrides
    def open(self):
        self.threshold = self.UiParameter(
            name="threshold",
            type=AttributeType.DOUBLE,
        ).value

        self.label = self.UiParameter(
            name="label",
            type=AttributeType.STRING,
        ).value

    @overrides
    def process_tuple(self, tuple_: Tuple, port: int) -> Iterator[Optional[TupleLike]]:
        if tuple_["score"] >= self.threshold:
            tuple_["label"] = self.label
            yield tuple_

Expected user workflow:

Step	User action	Texera behavior
1	User opens a Python UDF operator.	The Python code editor is shown as usual.
2	User writes self.UiParameter(name=..., type=...) declarations in the UDF class.	Texera detects supported parameter declarations.
3	User opens the operator properties panel.	Texera shows one row per inferred UI parameter.
4	User edits parameter values in the UI.	Parameter names and types stay locked; only values are editable.
5	User runs the workflow.	Texera persists the values, injects them into the Python UDF, and returns typed Python values through .value.
6	User changes the Python declarations.	Texera updates the inferred parameter structure while preserving matching existing values when possible.

Supported UDF classes:

Python UDF class	Supported
ProcessTupleOperator	Yes
ProcessBatchOperator	Yes
ProcessTableOperator	Yes
GenerateOperator	Yes

Supported UI parameter types:

Python declaration	UI/runtime type
AttributeType.STRING	string
AttributeType.INT / AttributeType.INTEGER	integer
AttributeType.LONG	long
AttributeType.DOUBLE	double
AttributeType.BOOL / AttributeType.BOOLEAN	boolean
AttributeType.TIMESTAMP	timestamp

Unsupported UI parameter types:

Python declaration	Behavior
AttributeType.BINARY	Rejected / ignored
AttributeType.LARGE_BINARY	Rejected / ignored

Reviewer-preferred implementation stack:

PR	Scope	Goal	PR
1	Frontend	Add parser, sync, type, and Formly component building blocks.	#5043
2	Scala backend	Add descriptor model and injection logic for persisted uiParameters.
3	Python backend	Add runtime support for declared UI parameters and typed value conversion.
4	End-to-end	Wire descriptors, UI, and runtime together and verify workflows.

sequenceDiagram
    autonumber

    actor User

    participant Code as Python UDF Code
    participant FE as Frontend Parser / UI
    participant Props as Operator Properties
    participant Scala as Scala Backend Injector
    participant Runtime as Python Runtime
    participant UDF as User UDF Class

    User->>Code: Declares self.UiParameter(...)
    Code->>FE: Python code changes
    FE->>FE: Infer parameter name + type
    FE->>Props: Expose editable parameter values
    User->>Props: Enters values
    Props->>Scala: Persist uiParameters with operator
    User->>Scala: Runs workflow
    Scala->>Runtime: Inject parameter values into Python code
    Runtime->>UDF: Execute operator
    UDF->>Runtime: Reads typed values via .value

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Acceptance criteria:

Area	Criteria
Authoring	Users can declare UI parameters in supported Python UDF classes with self.UiParameter(...).
UI behavior	Inferred parameter names and types are locked; parameter values are editable.
Value preservation	Existing values are preserved when code changes keep the same parameter names.
Runtime behavior	Python UDF code receives typed values from self.UiParameter(...).value.
Validation	Missing names/types, unsupported argument patterns, and binary/large-binary types are rejected.
Compatibility	Existing native operators and Python UDF workflows still execute.
Testing	Add focused frontend, Scala, Python, and browser/manual verification for the stacked changes.

Task Type

• Refactor / Cleanup
• DevOps / Deployment / CI
• Testing / QA
• Documentation
• Performance
• Other