bug(storage): ghost logs are protected from every retention pass, contradicting the cap comment #732

Problem (found during the #729 review; pre-existing)

isProtectedFromDebugPrune in src/main/storage/debugRetention.ts returns true for the entire ghost-logs bucket. Every prune pass — TTL, per-bucket cap, global budget — skips protected artifacts, so ghost logs are never pruned at all. The comments around the TTL pass and the ghost-logs cap ("keep ghost cleanup on the budget/cap passes … this cap handles abandoned session files") describe an intent the code does not implement. Introduced in 0e672c22.

Expected

Either the ghost-logs bucket is exempt from the TTL pass only (the documented reasoning: age alone is not evidence a log is disposable) and remains subject to its cap and the global budget with the usual active-grace guard, or the comments and the cap entry are removed and the bucket is documented as unbounded.

Impact

STATE_DIR/ghost-logs grows without bound; combined with #731 (resume re-appends the whole log) the per-session files themselves grow on every resume.

Refs #728, #729, #731.