Fix live IED identity and relay fault-record package download

[masarray]

Summary

Fixes two field interoperability defects reported against a SIPROTEC endpoint:

• resolves the physical IED name from the complete MMS Logical Device domain set, so a nested domain such as OCR7SJ8Mod2_MU1 cannot incorrectly rename the IED to OCR7SJ8Mod2 when sibling domains establish OCR7SJ8
• distinguishes non-zero extensionless files from directories and supports extensionless vendor fault-record packages such as FRA00019
• permits safe MMS FileOpen/FileRead paths without requiring a filename extension
• keeps normal CFG/DAT/CFF/ZIP grouping and safety limits unchanged

Regression coverage

• mixed domains: OCR7SJ8Application, OCR7SJ8CB1, OCR7SJ8Dc1, OCR7SJ8Mod2_MU1, OCR7SJ8V3p1_5051OC3phase1 => IEDName OCR7SJ8
• extensionless FRA00019 with a non-zero size is a downloadable file/package, not a directory
• extensionless zero-size entries remain directory candidates
• unrelated files such as TEST FILE.txt are not surfaced as fault records
• FileOpen accepts an extensionless remote filename

Protocol notes

The transfer still uses MMS FileDirectory, FileOpen, FileRead and FileClose with bounded traversal, byte limits, operation limits, cancellation and cleanup. COMTRADE completeness remains descriptive metadata; a single relay-provided package is classified as complete and downloadable.

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