Add --verbose flag to rocky estimate

[hugocorreia90]

rocky doctor gained a --verbose flag in #21 to surface extra detail (config paths, sizes, adapter types) in the text output path. The same pattern should apply to rocky estimate: a user diagnosing a cost estimate often wants the per-model EXPLAIN-plan raw output, which isn't currently surfaced.

Scope

Add --verbose to the Estimate command in engine/rocky/src/main.rs, thread it through run_estimate, and have the text output path print additional per-model detail (raw optimizer / EXPLAIN output, or extra cost breakdown — whatever the function already has on hand but doesn't currently print).

Out of scope: the JSON output. Do not change any *Output struct in rocky-cli/src/output.rs — that path cascades to Pydantic/TypeScript via just codegen. This issue is text-output-only.

Code refs

Line numbers refreshed against main 2026-06-14.

• engine/rocky/src/main.rs:1322 — Estimate { ... } enum variant (add the verbose: bool field here, mirroring Doctor)
• engine/rocky/src/main.rs:2989 — Command::Estimate { ... } dispatch arm and the run_estimate(...) call site
• engine/crates/rocky-cli/src/commands/estimate.rs:22 — run_estimate function signature and text output path
• Closed Add --verbose flag to rocky doctor #21 for the rocky doctor --verbose pattern to mirror (the Doctor { check, verbose } variant + dispatch is the template)

Acceptance criteria

• rocky estimate --verbose prints additional per-model detail in the text output
• rocky estimate (no flag) behavior is unchanged
• The JSON output is unchanged (no *Output struct edits)
• --help text for the flag is consistent with rocky doctor --verbose
• cargo test -p rocky-cli is green

Effort

2 hours.