explorer_agent reads wrong files when broken_file path has leading slash

[VinaySampath14]

When the Explorer agent identifies a broken file with a leading slash
(e.g. /src/agents/coder_agent.py instead of src/agents/coder_agent.py),
the file read fails silently and broken_file is set to empty string.

Expected: strip leading slash before attempting file read
Actual: silent failure, coder_agent receives empty broken_file

File: src/agents/explorer_agent.py