deployment: verify remaining hosted-install paths (ACM, operator, --secure, release URL, grant floors) #697

Follow-up to #692, which shipped the SQL-only two-phase installer (#694) and the restricted-environment runbook (#696). These items are documented as untested in docs/HOSTED-INSTALL.md / docs/ASSET-DISTRIBUTION.md and should be verified (or corrected) against real environments:

• Altinity Cloud (ACM) end to end: handlers via the ACM cluster setting config.d/sql-browser.xml, installer over HTTPS against the cluster endpoint, --cluster <literal name>; confirm File/file() and the stage-mode grants are available to the admin user; confirm the interserver <secret> is configured.
• clickhouse-operator end to end: handlers via CHI spec.configuration.files (config.d/sql-browser.xml), secret.auto, installer through the Service/LB; stage copies landing on different pods.
• --secure (native 9440 and HTTPS 8443) against a live server. Tests run plaintext only.
• Real GitHub release URL through the installer (--pull-url https://github.com/Altinity/altinity-sql-browser/releases/download/<tag>/sql.html). Only a manual url() fetch through the redirect was checked.
• Per-replica <user>/<password> interserver credentials (spike-verified, not in CI).
• Grant floors: least-privilege sets are "tested sufficient", but negative tests only cover REMOTE, URL and CREATE TEMPORARY TABLE (verify-only). Establish the single-node floor (likely FILE + DROP TABLE ON default.*) and per-mode minima.
• Release bundle: v0.7.3 does not ship deploy/; confirm the next tagged release bundle contains deploy/install.sh, uninstall.sh, lib/ and http_handlers.xml, and that install.sh --artifact sql.html works from it.
• ClickHouse Cloud: confirm the File engine/file() restriction, so the docs' "use the standalone runtime" guidance is accurate.

Deferred from #692 so that issue can close with the delivered, tested scope.