[BUG] Configuration error running import-agent

**Describe the bug**
Error when attempting to import bedrock agent to agent-core

**To Reproduce**
- `uv pip install bedrock-agentcore-starter-toolkit`
- `agentcore import-agent`
- US East (N. Virginia) (us-east-1)
- _my agent id_
- TSTALIASID
- langchain or strands, neither work.

**Expected behavior**
The import works

**Error Output**
```
╭─────────────────────────────────────────────────────────────── Configuration Error ────────────────────────────────────────────────────────────────╮
│ Failed to retrieve agent configuration! │
│ Error: ("{'type': 'http', 'name': 'bearerToken', 'in': 'header', 'bearerFormat': 'JWT', 'scheme': 'bearer'} is not valid under any of the given │
│ schemas", 'oneOf', deque(['components', 'securitySchemes', 'bearerToken']), None, [, │
│ ], [{'$ref': '#/definitions/Reference'}, {'$ref': '#/definitions/SecurityScheme'}], {'type': 'http', 'name': 'bearerToken', │
│ 'in': 'header', 'bearerFormat': 'JWT', 'scheme': 'bearer'}, {'oneOf': [{'$ref': '#/definitions/Reference'}, {'$ref': │
│ '#/definitions/SecurityScheme'}]}, deque(['properties', 'components', 'properties', 'securitySchemes', 'patternProperties', '^+$', 'oneOf']), │
│ None)
```

**Environment:**
- OS: macOS 26
- Python version: 3.13
- Package version: 0.1.12
- Installation method: uv

Start by running the documented `agentcore import-agent` flow with the stated region, agent ID, alias, and package version, then inspect where the configuration error is produced. Done means importing the Bedrock agent succeeds for the reported langchain or strands setup without the schema-validation failure.

Written by the indexing model from the issue text.