Manifest/CSV manual asset inventory

[mfaferek93]

Merge hand-authored or CSV-imported asset entries into the entity tree via the existing manifest discovery.

• CSV columns: id, manufacturer, model, serial, hardware_rev, firmware, endpoint, role, plus extensible extras; entries become Components with identity populated.
• Imported entries merge with protocol-discovered structure; a malformed row is skipped with a warning instead of aborting the import.
• Acceptance: a CSV/manifest asset appears in the tree and merges with discovered structure, with per-field source provenance.