fix: clarify gateway-connector help text

[jariy17]

Summary

• agentcore project add gateway-connector --help didn't list the accepted values for --connector. Add `[bedrock-knowledge-bases | web-search]` to the description so users can discover them without reading the source.
• --knowledge-base claimed to accept a "project Knowledge Base name or external ten-character ID", but project-owned Knowledge Bases are not implemented — the handler passes the string straight through as `knowledgeBaseId`. Drop the false claim.

Before

```
--connector curated connector
--knowledge-base project Knowledge Base name or external ten-character ID; only for bedrock-knowledge-bases
```

After

```
--connector curated connector [bedrock-knowledge-bases | web-search]
--knowledge-base external ten-character Knowledge Base ID; only for bedrock-knowledge-bases
```

Test plan

• `bun run build`
• `agentcore project add gateway-connector --help` shows the updated text
• No behavior change — the enum on `--connector` and the pass-through of `--knowledge-base` were already what the code did; this only aligns the help text with reality

[agentcore-devx-automation]

Claude Security Review: no high-confidence findings. (run)

[agentcore-devx-automation]

AgentCore Harness Review

Verdict: Looks good

Small, doc-only change updating two flag descriptions in src/handlers/project/add/gateway-connector/index.ts.

• The added enum hint on --connector ([bedrock-knowledge-bases | web-search]) matches the zod enum on the next line.
• The --knowledge-base description change aligns with actual handler behavior: connectorTargetFromShortcut (lines 101–126) passes the string straight through as knowledgeBaseId with no project-KB resolution, and per the commit message project-owned KBs aren't implemented yet. Note that src/projectSchemas/project.ts (~lines 183–207) still tolerates a project-KB name as a valid reference, so if/when that flow is wired up end-to-end the help text may need to be widened again — but for now the new wording is more accurate than the old one.

No code changes required.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.98%. Comparing base (81f5af2) to head (84c3dca).
⚠️ Report is 1 commits behind head on refactor.

Additional details and impacted files

@@            Coverage Diff            @@
##           refactor    #2235   +/-   ##
=========================================
  Coverage     96.98%   96.98%           
=========================================
  Files           564      564           
  Lines         39226    39226           
=========================================
  Hits          38042    38042           
  Misses         1184     1184           

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[github-actions]

Thanks for the report, @codecov-commenter — feedback like this is exactly
how we catch the things we missed. Because this PR is already
closed, the team won't see follow-up comments here.

Would you mind opening a new issue so we can track it properly?
https://github.com/aws/agentcore-cli/issues/new/choose

If this is a security issue, please report it privately via
https://aws.amazon.com/security/vulnerability-reporting/ instead
of a public issue.