- #2741: Pass inheritedModel as fallback in subagent-resolver when user hasn't
configured an override, ensuring custom provider models take priority
- #2648: Fix getPlanProgress to treat plans with 0 checkboxes as incomplete
instead of complete (total > 0 && completed === total)
- #2779: Relax Hephaestus single-task guard to accept multi-step sub-tasks
from Atlas delegation, only rejecting genuinely independent tasks
Fixes#2741, fixes#2648, fixes#2779
Align runtime defaults, tests, docs, and generated artifacts with the newer GPT-5.4 baseline. Keep think-mode and prompt-routing expectations consistent after the model version bump.
Split monolithic hephaestus.ts into directory with model-specific prompt
variants (gpt-5-4.ts, gpt-5-3-codex.ts, gpt.ts) mirroring the
sisyphus-junior pattern. Generic gpt.ts uses pre-codex-tuning prompt as
fallback for non-specific GPT models.
Also adds isGpt5_4Model and isGpt5_3CodexModel helpers to types.ts.
YeonGyu-Kim