fix(cli): preserve ordinary scrape and search output

[developersdigest]

Summary

Preserve ordinary scrape/search output and diagnostics: honor multi-URL JSON/file output, add shared receipts, save structured failures before nonzero exit, keep empty search output, expose search --pretty, and report available retry/cache metadata. Add validated millisecond scrape --timeout and update CLI guidance.

Deferred from #245 so Alexandria can be reviewed separately. This draft is stacked on #245 for its shared receipt/error helper; merge that first and retarget this PR to main.

Validation

TypeScript build and 140 tests passed across six affected suites, including compiled CLI calls against a local HTTP fixture. Reduced redundant new coverage; retained order/partial-failure/file-output checks and command-level pretty/timeout/error regressions. No paid API calls.

Boundaries

Related: Exchange #548, #556, #547, #567. No API changes; server billing/cache policy is unchanged. All-command normalization beyond search/scrape remains separate.

Explicit multi-URL output is JSON regardless of extension. Failed single calls write JSON to requested files, including non-JSON filenames; successful raw text remains pipeable. Missing charge metadata means unknown. Retry hints are preserved only when supplied by the transport/SDK.

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Summary by cubic

Preserves ordinary scrape and search output while making structured output and failures consistent. Multi-URL scrape now honors --json and -o with an ordered JSON array, while failed requests write structured errors before the command exits nonzero; raw single-URL output remains pipeable.

CLI behavior

• Adds receipts with reported credits, request and operation IDs, plus cache and retry diagnostics on stderr.
• Keeps empty search responses and metadata in JSON and file output, and adds search --pretty.
• Adds validated scrape --timeout <ms> support and disables automatic resume when it is set.
• Keeps default multi-URL scraping as per-URL files, while reporting failed URLs without creating files for them.
• Updates the README and skill guides with output, billing, retry, timeout, and recovery guidance.

^{Written for commit 0811001. Summary will update on new commits.}