[Atlassian MCP] Add getJiraIssueWatchers tool

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

The Atlassian MCP currently exposes getJiraIssue with an expand=watches option, but
this only returns a watch count and an isWatching boolean for the authenticated
user — not the list of watchers. There's no way to enumerate who is watching an
issue.

Proposed Solution

A new tool (e.g. getJiraIssueWatchers) wrapping the existing Jira REST endpoint:

GET /rest/api/3/issue/{issueIdOrKey}/watchers

Returns: watchCount, watchers[] (accountId, displayName, emailAddress, active).

Alternative Solutions

None via the MCP. The only path is manually checking the Jira UI per ticket.

Priority

Medium - Would be very helpful

Feature Category

CLI commands and flags

Use Case Example

I'm using Claude Code to automate a weekly stakeholder update workflow:

1. Search Jira for tickets my team completed this week
2. Identify external stakeholders (non-team members) to notify
3. Draft and post a Slack message tagging each stakeholder

Currently I can identify stakeholders via the reporter field, but reporter-only
coverage misses people who are watching a ticket without having filed it (e.g. a
manager or downstream team member added as a watcher). Without watcher enumeration,
the stakeholder list is incomplete and I have to manually look up watchers in the
Jira UI.

Additional Context

• The endpoint requires browse permission on the issue, which is already satisfied

by the existing read:jira-work scope.

• No new OAuth scopes needed.