fix(fiori-mcp): validate metadata output directory

[Pybsama]

Description

Fixes #4981.

download_odata_service_metadata now rejects a missing appPath before system lookup, metadata download, or file writes. The exposed input schema now states that the output directory must already exist, that this tool does not create directories, and that generate_fiori_app_odata should be used when creating a new application. This also adds regression coverage and a patch changeset.

AI assistance: OpenAI Codex was used to assist with issue analysis, implementation, test authoring, and review. I reviewed the changes and test results; no third-party material was intentionally included.

Type of change

• Bug (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds a new feature)
• Breaking change (Bug or New feature that would cause existing functionality/consumers to not work as expected)
• Non-Breaking chores (Changes to tools, libraries, build process, documentation, etc)
• None of the above (Reviewers might ask for more clarification)

How have you tested?

• Focused tool and schema tests: 24 tests and 8 snapshots passed.
• @sap-ux/fiori-mcp-server test suite: 31 suites, 396 tests, and 35 snapshots passed.
• Repository test target: 87 of 87 projects succeeded.
• Repository lint target: 95 of 95 projects succeeded with no errors.
• Repository build target: 92 of 92 projects succeeded.
• Prettier, changeset validation, and git diff --check passed.

Checklist:

• The code conforms to the general development principles
• Supplied as many details as possible on this change
• The code is easy to read and maintainable by others
• Corresponding changes to the documentation has been done
• Already existing and new unit tests pass locally

[changeset-bot]

🦋 Changeset detected

Latest commit: 3576ef0

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@sap-ux/fiori-mcp-server	Patch

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