feat(reports): add partial name filter to list_reports

[dmitrijs-pavlovs-dev]

list_reports now accepts an optional name and sends it as the API's server-side nameContains filter, so case-insensitive partial matching applies before pagination. The parameter is defined once in Zod and appears in both the derived stdio schema and the hosted argument schema.

Demo-mode searches now apply the same name matching to the sample reports and return the matching row count. Previously a search such as name: "cloud cost" returned all three samples; it now returns only the matching report. Searches with no match follow the handler's existing No reports found response, and searches without a name still return all samples.

Regression tests reproduced the demo bug before the fix. They cover case-insensitive partial matches, multiple matches, no matches, empty and omitted names, fixture preservation, and the real demo-token handler without HTTP calls. The existing request-mapping test verifies the production API parameter.

Validation after synchronizing with main: 1,471 unit tests, 320 integration tests, yarn check:dev, build, and whitespace checks passed. This change used deterministic validation and makes no new live API claim. No standalone validation documentation is included.