Add athq subcommand to run Athena queries

[waltervargas]

Summary

Adds a top-level ewcli athq command that runs an Athena query synchronously and prints the result rows. Designed for the AWS CloudShell workflow: wget the binary from a release, then run ewcli athq "SELECT ..." using the active console credentials.

• Uses the existing aws-sdk-go v1 dependency (no new SDK pulled in).
• Credentials/region resolved from the standard AWS chain (env vars, shared config, instance/role) — works out of the box in CloudShell.
• Polls GetQueryExecution until the query reaches a terminal state, then streams GetQueryResultsPages to stdout.
• Flags: --database/-d, --catalog/-c, --workgroup/-w (default primary), --output-location/-o, --region/-r, --format/-f (tsv or csv), --poll-interval.
• Status line (ewcli: athena query <id>) goes to stderr so stdout stays clean for piping.

Example

ewcli athq -d walterdb "SELECT * FROM AwsCatalog.walterdb.waltertable;"

If the workgroup has no default result location, pass -o s3://bucket/prefix/.

Test plan

• go build ./... succeeds
• go vet ./... clean
• ewcli athq --help renders flags as expected
• ewcli --help lists athq alongside aws
• Run against a real Athena workgroup in CloudShell to confirm end-to-end behavior

---

Generated by Claude Code