Fixes
- Codex SessionStart hook no longer fails at startup. When a hook errored before its handler ran (missing
session_id, invalid cwd, or a missing transcript path), claude-mem fell back to a bare {"continue":true} regardless of which hook fired. Codex's strict SessionStart validator rejects that shape as "invalid session start JSON output," breaking context injection at Codex startup. The fallback now emits a valid hookSpecificOutput: { hookEventName: "SessionStart", additionalContext: "" } for the context hook, matching what Codex expects.
- Fixed a related gap where the Codex adapter silently dropped an explicit empty-string
additionalContext from its output instead of preserving it, which could leave the SessionStart payload incomplete.
Closes #2947, #2972. Supersedes #2953 and #2948.
