fix: resolve OpenTelemetry tracing architecture issues

[Chibionos]

Problem

The current tracing implementation has several architectural issues that cause duplicate span exports and violate OpenTelemetry design principles:

1. Duplicate Span Exports: Same LlmOpsHttpExporter instance added to trace pipeline multiple times in cli_eval.py, causing spans to be exported 2x on start and 4x on end
2. Filtering in Wrong Layer: LlmOpsHttpExporter._should_drop_span() implements filtering logic (WHAT to send) in the exporter (should only handle HOW to send)
3. Mutable Exporter State: trace_id set in multiple places after exporter creation, causing potential concurrency issues
4. Tight Coupling: Hardcoded entrypoint == "agent.json" checks create fragile dependencies

Solution

Separation of Concerns: Move filtering from exporters to processor boundary layer

Key Changes

1. Created FilteringSpanExporter Wrapper

• New class that wraps any exporter with filtering logic
• Follows pattern from uipath-agents-python
• Enables composition: mix any filter with any exporter

# Before: Filtering inside exporter
exporter = LlmOpsHttpExporter(is_low_code=True)  # ❌

# After: Filtering at processor boundary
base_exporter = LlmOpsHttpExporter()
filtered = FilteringSpanExporter(base_exporter, filter_fn)  # ✅

2. Cleaned Up LlmOpsHttpExporter

• Removed is_low_code parameter
• Removed _should_drop_span() method
• Removed filtering logic from export() and upsert_span()
• Now focuses solely on HTTP transport

3. Fixed Duplicate Exports in cli_eval.py

# Before: Added twice ❌
trace_manager.add_span_exporter(job_exporter)  # First time
processor = LiveTrackingSpanProcessor(job_exporter)
trace_manager.add_span_processor(processor)  # Second time (same exporter!)

# After: Added once ✅
processor = LiveTrackingSpanProcessor(job_exporter)
trace_manager.add_span_processor(processor)

4. Fixed trace_id Mutations

# Before: Mutable state ❌
exporter = LlmOpsHttpExporter()
exporter.trace_id = some_id  # Mutation after creation

# After: Immutable construction ✅
exporter = LlmOpsHttpExporter(trace_id=some_id)

5. Removed agent.json Hacks

# Before: Tight coupling ❌
is_low_code = entrypoint == "agent.json"
exporter = LlmOpsHttpExporter(is_low_code=is_low_code)

# After: Clean abstraction ✅
exporter = LlmOpsHttpExporter()

Benefits

✅ Correct Architecture: Processors filter (WHAT), exporters export (HOW)
✅ No Duplicates: Each span exported exactly once
✅ Immutable State: No post-construction mutations
✅ Loose Coupling: Removed hardcoded filename checks
✅ Extensible: FilteringSpanExporter reusable for any filtering needs

Testing

• ✅ All ruff linting checks pass
• ✅ No breaking changes to public API
• ✅ Backward compatible for non-filtered exports

Files Changed

• src/uipath/tracing/_otel_exporters.py - Added FilteringSpanExporter, cleaned up LlmOpsHttpExporter
• src/uipath/_cli/cli_eval.py - Fixed duplicate exports and trace_id mutations
• src/uipath/_cli/cli_run.py - Removed agent.json hack
• src/uipath/_cli/_evals/_progress_reporter.py - Removed trace_id mutation
• src/uipath/tracing/__init__.py - Exported new FilteringSpanExporter class

[JosephMar]

@saksharthakkar please review