## Why
The token-budget feature currently adds remaining-token messages
whenever usage crosses the 25%, 50%, and 75% thresholds. Those periodic
inserts create prompt churn without requiring action, while the
near-compaction reminder and explicit `get_context_remaining` tool
already cover actionable and on-demand budget information.
The context-window lineage block is also easier to scan as plain labeled
text than as a `<token_budget>`-wrapped fragment.
## What changed
- Stop recording automatic remaining-token messages at percentage
thresholds.
- Render context-window lineage in `First`, `Current`, `Previous` order
with colon-separated labels.
- Omit the `Previous` line for the first context window.
- Remove `<token_budget>` wrappers from newly rendered lineage,
near-compaction reminders, and `get_context_remaining` output.
- Keep recognizing legacy wrapped fragments so existing rollouts remain
compatible.
- Remove the post-sampling token snapshot that was only needed by the
periodic threshold path.
## Testing
- `just test -p codex-core token_budget` (11 tests passed)
pakrym-oai
aaf737fa59