replay command crashes with unhandled ParseError on malformed input

[Pragathi04-k]

Description
The replay command crashes when executed on a malformed telemetry stream (samples/malformed_frame.sgf) instead of handling the parsing failure gracefully.

Instead of returning a structured diagnostic or user-friendly error message, the CLI terminates with an unhandled traceback.

Root Cause Analysis
The issue appears to originate in the replay workflow where Engine().process(data) raises a ParseError that is not caught.

Traceback path:
sigflow/cli/commands.py -> replay_command() -> Engine().process() -> parser.parse()

Specifically:

• sigflow/parsers/base.py
• require() raises:

ParseError("truncated input", offset=offset)

This exception propagates upward without being handled inside the CLI replay command.

Steps to Reproduce

1. Clone the repository
2. Install dependencies

pip install -e ".[dev]"

3. Run:

python -m sigflow replay samples/malformed_frame.sgf

Actual Behavior
The command crashes with an unhandled exception:

sigflow.core.exceptions.ParseError: truncated input

Expected Behavior
The CLI should handle malformed input gracefully by:

• showing a structured diagnostic message, or
• returning a controlled error message without a full traceback

Example:

error: malformed stream - truncated input at offset X

Impact
This affects reliability and usability of the replay workflow, especially since the framework is intended to process malformed or forensic telemetry streams. A malformed sample file causing a CLI crash can interrupt automation or debugging pipelines.

[jmestwa-coder]

Before moving toward a fix, can you first verify whether replay is expected to surface raw parser exceptions for debugging workflows, or whether it should match the behavior of other CLI commands that convert parsing failures into user-facing diagnostics?

If there are existing commands in the CLI that already handle ParseError gracefully, referencing those would help confirm the intended behavior and keep any fix aligned with the current CLI error-handling design.