体验：describe 缺参不说用 catalog 列出工具

体验问题：describe 缺参不说用 catalog 列出工具

Skip: catalog empty search (#56), schema missing args (#58), grok not in catalog (#59), and doctor vs diagnose (#54). This is all-cli describe.

Current design

all-cli describe <tool> uses cobra.ExactArgs(1). With no ID it prints cobra's generic:

Error: accepts 1 arg(s), received 0

Unknown IDs already go through unknownToolIDError (did you mean). Missing IDs do not name all-cli catalog, which is the discovery command.

Why this is a problem

1. Operators who found describe in --help still do not know how to get a valid ID.
2. catalog is the list; describe is the detail. The error path does not connect them.
3. Schema's missing-arg message was fixed separately. Describe still uses ExactArgs.

Suggested change

Replace ExactArgs with a check that returns describe needs a tool ID. List tools: all-cli catalog. Keep unknown-ID suggestions. Do not change catalog matching or the grok registry in this pass.

Start at the all-cli describe command's argument validation and run it without a tool ID to observe the current Cobra error. Done means the missing-ID path says describe needs a tool ID. List tools: all-cli catalog, while unknown-ID suggestions and catalog matching remain unchanged.