CLI: curl-style entrypoint (cli.py)

[GeoSpark]

The curl-style CLI. See DESIGN.md §10.

Scope

• cli.py (rich-click): stac-validator-plus <ITEM> with -o/--output, --json, --config, --model, --region, --examine-runs, --timeout, --max-concurrent, --no-plugin, --no-check, --wall-clock-budget, --token-budget. (No --max-turns — there is no agentic loop in a Bedrock Messages call.)
• stdout by default; -o writes file (auto-name when given a dir); --json also emits raw canonical JSON.

Depends on

#13

Test approach

TDD with Click's CliRunner: stdout default, -o file/dir, --json, flag->Settings override. Pipeline mocked.

Acceptance

• Flags map to Settings; curl-style output behaviour.
• Exit codes sane (gated/invalid vs clean).