[Bug]: confluence_get_page_history / get_page_diff always fail under OAuth (v2 version objects have no "id")

[Code-by-AB]

Prerequisites

• Searched the existing issues; this has not been reported.
• Checked the README.

Bug Description

confluence_get_page_history and confluence_get_page_diff fail for every page and every version number (including the current one) when the server uses OAuth 2.0 with granular scopes, raising Version {n} not found for page '{id}'.

Under OAuth the call routes to ConfluenceV2Adapter.get_page_by_version() in src/mcp_atlassian/confluence/v2_adapter.py, which maps a version number to a version id:

if ver.get("number") == version:
    version_id = ver.get("id")          # always None
...
raise ValueError(f"Version {version} not found for page '{page_id}'")
url = f"{self.base_url}/api/v2/versions/{version_id}"   # not a real endpoint

But Confluence v2 version objects from GET /api/v2/pages/{id}/versions have no id field. Verified against the live API, the keys are number, message, minorEdit, authorId, createdAt, page. So ver.get("id") is always None and the lookup always raises. get_page_diff calls get_page_history for both versions, so it fails too.

Two deeper issues beyond the id bug:

1. There is no GET /api/v2/versions/{id} endpoint.
2. No v2 endpoint returns a historical version's body (the version endpoints are metadata-only), so even with the id lookup fixed, the OAuth/v2 path cannot return historical content.

The v1 fallback GET /rest/api/content/{id}?status=historical&version=N&expand=body.storage returns 401 "scope does not match" under granular OAuth scopes, so it is not available to OAuth apps either.

Steps to Reproduce

1. Run the server with OAuth 2.0 + granular scopes against a Confluence Cloud site.
2. Call confluence_get_page_history with a valid page_id and version (e.g. the page's current version number).
3. See the error. Same for confluence_get_page_diff with any two versions.

Expected Behavior

get_page_history returns the requested version (ideally with body) and get_page_diff returns a diff. At minimum, version metadata should be retrievable under OAuth.

Actual Behavior

Error getting page history: Failed to get page '<id>' version 8: Version 8 not found for page '<id>'

Fails for every version number, including the page's current version.

mcp-atlassian Version: 0.21.1
Installation Method: From PyPI (uvx mcp-atlassian)
Operating System: Windows
Python Version: 3.13.13
Atlassian Instance Type: Confluence Cloud
Client Application: Claude Code (MCP client)

Additional Context / suggested fix

• For history, match on number and return the version metadata from /pages/{id}/versions (this works under OAuth).
• Returning a historical body (and therefore the diff) is not possible via v2; it requires the v1 content API, which granular-scope OAuth apps cannot call. Consider documenting that body/diff need API-token auth, and make get_page_diff fail with a clear, actionable message under OAuth instead of Version not found.
• Buggy line is version_id = ver.get("id") in get_page_by_version (around line 822 on the v0.21.1 tag).