Module execution_history 

Historical execution duration tracking for ETA estimation.

Responsibilities:

• Record phase durations for completed task executions.
• Provide weighted average calculations for ETA estimation.
• Persist data to .ralph/cache/execution_history.json.

Not handled here:

• Real-time progress tracking (see app_execution.rs).
• Actual rendering of progress indicators.

Invariants/assumptions:

• Historical data is keyed by (runner, model, phase_count) for accuracy.
• Recent runs are weighted higher (exponential decay).
• Maximum 100 entries per key to prevent unbounded growth.

Structs

ExecutionEntry

A single execution entry recording phase durations.

ExecutionHistory

Root execution history data structure.

Functions

get_phase_averages

Get historical average durations for all phases.

load_execution_history

Load execution history from cache directory.

record_execution

Record a completed execution to history.

save_execution_history

Save execution history to cache directory.

weighted_average_duration

Calculate weighted average duration for a specific phase.