[SaladDay]

Each terminal Runtime preparation result now carries the Runtime-measured duration_ms. Core records one step per confirmed operation (file, skill, plugin, configure, npm, python, setup with its index, finalize), logs one Environment initialization step line per step, and stores the list on the Environment so it survives a failed initialization.

An Environment that fails without a confirmed failed step now records a private failure category (timeout, runtime_disconnected, unconfirmed, rejected, operation_failed, core_error, core_restart, compute_released). The public reason is unchanged.

Session diagnostics return initialization_steps and params.category; the Web Session page shows an Initialization row and the category sentence.

• Wire: docs/runtime-protocol.md
• Diagnostics: contracts/agents-api/session-diagnostics.md, contracts/agents-api/core-errors.md
• Migration 000009_environment_initialization_steps.sql

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