## Intent
Keep Bazel and Starlark files consistently formatted without requiring
contributors to install or version buildifier themselves.
## Implementation
- Add a SHA-256-pinned, cross-platform DotSlash manifest for buildifier
v8.5.1.
- Run buildifier from the shared `just fmt` and `just fmt-check` driver,
with Windows-safe explicit DotSlash invocation.
- Provision DotSlash in formatting CI and contributor devcontainers, and
document the source-build prerequisite.
- Apply the initial mechanical buildifier formatting baseline.
## Why
Goal steering prompts have grown into long inline Rust strings, which
makes the authored prompt text hard to review and easy to damage while
changing the surrounding plumbing. Moving those prompts into embedded
Markdown templates keeps the policy text in the shape reviewers actually
read, while preserving the existing runtime substitution and objective
escaping behavior.
## What changed
- Added `ext/goal/templates/goals/continuation.md`, `budget_limit.md`,
and `objective_updated.md` for the three goal steering prompts.
- Updated `ext/goal/src/steering.rs` to parse those embedded templates
once with `codex-utils-template` and render the existing goal values
into them.
- Kept user objectives XML-escaped before rendering and converted budget
counters into template variables.
- Added the template directory to `ext/goal/BUILD.bazel` `compile_data`
so Bazel has the same embedded prompt inputs as Cargo.
## Testing
- Not run locally.
## Why
The goal extension needs more context when a turn starts than
`turn_store` alone provides.
In particular, goal accounting needs the stable turn id, the effective
collaboration mode, and the cumulative token-usage baseline captured at
turn start so it can:
- suppress goal accounting for plan-mode turns
- compute exact per-turn deltas from cumulative `total_token_usage`
snapshots instead of relying on the most recent usage event alone
- keep the extension-owned accounting path aligned with the host turn
lifecycle
## What
- extend `codex_extension_api::TurnStartInput` to expose `turn_id`,
`collaboration_mode`, and `token_usage_at_turn_start`
- pass the full `TurnContext` plus the captured token-usage baseline
through the turn-start lifecycle emission path
- initialize goal turn accounting from the turn-start baseline and
collaboration mode
- switch goal token accounting to compute deltas from cumulative
`total_token_usage` snapshots
- add coverage for the new turn-start lifecycle fields and for
goal-accounting baseline behavior
## Testing
- added `turn_start_lifecycle_exposes_turn_metadata_and_token_baseline`
in `codex-rs/core/src/session/tests.rs`
- added `ext/goal/tests/accounting.rs` coverage for baseline-aware goal
accounting and plan-mode suppression
