Rename remaining OSI references to Ossie

[jbonofre]

Summary

Completes the OSI → Ossie rename across the repository, covering the parts that still carried the former name. 135 files changed (57 file/directory renames, the rest content edits).

Rebased onto current main (1d9ebce).

Structural renames

• core-spec: osi-schema.json → ossie-schema.json — including its $id and every reference (examples, docs, ROADMAP, python tests, and the Java schema-loader / pom resource copy).
• Python package: OSI* model classes → Ossie* (OssieDocument, OssieDataType, OssieSemanticModel, …); to_osi_json/to_osi_yaml → to_ossie_*.
• Converters (Python): package/dir renames (osi_omni → ossie_omni, honeydew_osi → honeydew_ossie) plus source, test, and fixture files (osi_to_msi.py, test_osi_converter_*.py, tpcds_osi.yaml, …).
• Converters (Java): Osi* classes → Ossie* (files kept in sync with class names); ALL_CAPS constants → OSSIE (e.g. SALESFORCE_TO_OSSIE); CLI direction flag toOSI/"toosi" → toOssie/"toossie".

Former-name references outside the osi token

• Pre-donation GitHub org: 3 links to github.com/open-semantic-interchange/Ossie → github.com/apache/ossie, in converters/orionbelt/tests/test_ossie_tpcds_baseline.py and converters/orionbelt/ossie_obml_mapping_analysis.md. Two also had a stale path — converters/index.md does not exist here, so they now point at converters/README.md, which carries the heading the anchor targets.
• NVIDIA converter: dropped the "Open Semantic Interchange" PyPI keyword, aligning it with the other nine packages ("Apache Ossie", "Ossie", "<Vendor>").

Integration with newer main commits

Three references in code merged since this branch was opened pointed at names this PR renames:

• converters/nvidia/tests/test_converter.py — schema path core-spec/osi-schema.json → ossie-schema.json (from [OSSIE][NVIDIA_GSF] Add bidirectional GSF semantic model converter #247/[OSSIE][NVIDIA_GSF] Rename GSF converter directory and package to NVIDIA #299).
• converters/dbt/tests/test_ossie_to_msi.py — the SUM_BOOLEAN tests (fix(dbt): resolve SUM_BOOLEAN semantic model for qualified columns #292) used _osi_doc/_osi_dataset/_osi_field/_osi_metric/OSIToMSIConverter, all renamed here; left as-is they would raise NameError.
• python/README.md — kept both the "fundation" → "foundation" typo fix (Fix typo in python README.md #284) and the OSI documents → Ossie documents rename on the same line.

Intentionally preserved

• The historical note "formerly known as Open Semantic Interchange (OSI)" in README, CONTRIBUTING, and docs.
• License :: OSI Approved :: Apache Software License in converters/gooddata/pyproject.toml — that OSI is the Open Source Initiative, and the PyPI trove classifier is invalid under any other spelling. An earlier revision of this branch had renamed it, which broke the gooddata package build.
• English words that merely contain the substring (position, composite, repository, cosine, posix, …) are untouched.

Known remaining item, not addressed here

docs/index.md:339 and docs/working_groups.md:22 still link the former opensemanticx Slack workspace, while the four working-group channels in docs/working_groups.md live in apache-ossie.slack.com — so anyone following the join link lands in the wrong workspace. Left alone because there are two competing apache-ossie invite tokens in the tree (zt-42zw4rflt-… in README/CONTRIBUTING, zt-42i1xkgy8-… in docs/index.md:367) and substituting a dead invite would be worse than the stale link. Worth a follow-up once someone confirms which invite is live.

[QMalcolm]

Looks like we have a small merge conflict, but otherwise looks good to me!