fix(oci-cloud): dispatch pagination by SDK contract and preserve native responses

[dustin-sale]

Description

Addresses #477 in the local worktree based on f99eeca09b42987a71a4568605f7efc611932269 (including the new test_native_pagination.py file).

Pagination selection now uses SDK continuation arguments rather than list_/summarize_ prefixes or limit alone. Scalar responses serialize normally. Native SDK envelopes with a single declared record array retain their shape and aggregate records; Identity Domains resources support OPC page tokens and SCIM start_index/count traversal. Original per-page non-record metadata is exposed in result_meta.page_metadata. Scalar and ambiguous multi-array paged aggregates remain intact as single-page payloads with explicit next_page continuation rather than speculative metric merging.

Existing raw-list, items, DNS, Logging Search results, and Object Storage behavior remains covered. Capped results report has_more_results in full and summary modes, expose continuation only at lossless page boundaries, and reject repeated/no-progress traversal. SCIM count=0 remains a metadata-only query. Updated README and changelog. No dependency changes.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• This change requires a documentation update

How Has This Been Tested?

• From repository root: moon run oci-cloud-mcp-server:test — 226 passed; 92.98% branch-inclusive coverage, exceeding the configured 90% gate.
• From repository root: moon run root:lint — passed.
• From repository root: git diff --check — passed.

Regression tests exercise production public-method validation, dispatch, serialization, full/summary result shaping, real SDK envelopes, token and SCIM traversal, truncation, metadata-only queries, and no-progress failures. Execution is mocked; no live OCI calls were made.

Test Configuration:

• Firmware version: N/A
• Hardware: Docker sandbox
• Toolchain: Python 3.13.15, locked uv environment, pytest 9.0.3, FastMCP 3.4.5
• SDK: OCI Python SDK 2.185.1

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code (author attestation not supplied)
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings (uv emits an existing UV_NATIVE_TLS deprecation warning)
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules (N/A; none required)

This is a validation proposal only, not a published PR. OCA/signoff and publication prerequisites have not been verified.