v0.3-T3 — ahc cost-estimate (plan-level cost estimation CLI)

[sv-pro]

Summary

Implement ahc cost-estimate <plan-file> — estimate total cost for a declared plan using CostProfileStore percentiles when available, falling back to static pricing.

Depends on: #122 (cost-profile CLI + runtime wiring)

Scope

• Parse a plan file (YAML or JSON) specifying steps with model, action, and token bounds
• Use CostProfileStore percentiles (p50/p90/p99) when trace profiles exist for the (action_name, model_name) pair
• Fall back to static pricing from PricingRegistry when no profiles exist
• Output: three-point estimate (optimistic / expected / worst-case) per step and total
• Machine-readable output option (--json)

Key Files

• src/agent_hypervisor/compiler/cli.py — add cost-estimate command
• src/agent_hypervisor/economic/cost_estimator.py — estimate_plan_cost()
• src/agent_hypervisor/economic/cost_profile_store.py — CostProfileStore.percentile()
• tests/compiler/test_cost_estimate.py — new test file

Acceptance Criteria

• ahc cost-estimate <plan> prints per-step and total estimates
• Uses trace profiles when available, static pricing when not
• --json flag outputs machine-readable estimates
• pytest tests/compiler/test_cost_estimate.py -v passes

Milestone

v0.3