Preserve stack traces in exception log messages

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DISCLOSURE: LLM-GENERATED TEXT

Problem

Several runtime and editor catch blocks interpolate only Exception.Message into Unity logs. This discards exception types, inner exceptions, and stack traces needed to diagnose failures. Pool purge logging is corrected in #761, but the repository-wide sweep spans unrelated systems and should land separately.

Acceptance criteria

• Inventory Debug.Log* calls that log caught exceptions through .Message alone.
• Log the full exception while retaining useful operation context.
• Avoid duplicating exceptions already included through ToString() or equivalent output.
• Preserve deliberately user-facing validation messages that are not diagnostic logs.
• Add a focused guard only if it distinguishes diagnostic logs without false positives.