feat: Add Jira Service Management Connector

/claim #2281

Summary

Adds a new Jira Service Management (JSM) connector as a thin subclass of the existing Jira connector, addressing Issue #2281.

Approach

After reviewing the feedback on PR #7008 and PR #9121, I chose the thin subclass approach — no code duplication, no copy-paste. The JSM connector inherits all logic from JiraConnector and overrides only what differs:

document_source property → returns DocumentSource.JIRA_SERVICE_MANAGEMENT
Constructor → accepts jira_service_management_base_url instead of jira_base_url

This is possible because JSM uses the same underlying Jira APIs and authentication.

Changes

Backend

File	Change
`backend/onyx/configs/constants.py`	Add `JIRA_SERVICE_MANAGEMENT` to `DocumentSource` enum + description
`backend/onyx/connectors/jira/connector.py`	Add `document_source` property to `JiraConnector`; add `source` param to `process_jira_issue()`
`backend/onyx/connectors/jira_service_management/__init__.py`	New module
`backend/onyx/connectors/jira_service_management/connector.py`	`JiraServiceManagementConnector` — thin subclass of `JiraConnector`
`backend/onyx/connectors/registry.py`	Register JSM connector in `CONNECTOR_CLASS_MAP`
`backend/ee/onyx/external_permissions/sync_params.py`	Add JSM to permission sync config (reuses Jira sync functions)

Frontend

File	Change
`web/src/lib/types.ts`	Add `JiraServiceManagement` to `ValidSources` enum + auto-sync sources
`web/src/lib/sources.ts`	Add JSM source metadata (uses `JiraIcon`)
`web/src/lib/connectors/connectors.tsx`	Add JSM connector form config + `JiraServiceManagementConfig` interface
`web/src/lib/connectors/credentials.ts`	Add JSM credential defaults (reuses `JiraCredentialJson`)
`web/src/lib/connectors/AutoSyncOptionFields.tsx`	Add JSM auto-sync entry
`web/src/components/admin/connectors/ConnectorTitle.tsx`	Add JSM connector title handling

Key design decisions addressing prior PR feedback

No code duplication (P0 from #9121 review) — thin subclass, shared logic stays in jira/
Uses ConnectorMapping not ConnectorDescriptor (P0 from #7008 review)
DocumentSource.JIRA_SERVICE_MANAGEMENT properly added to enum (P0 from #7008 review)
Frontend field names match backend — jira_service_management_base_url only, no stale jira_base_url (P2 from #7008 review)
No dead/unused code — no copy-pasted utilities (P2 from #9121 review)
Modern Python typing — uses list not List (P2 from #9121 review)

Testing

The JSM connector inherits all behavior from the Jira connector. It can be tested by:

Creating a JSM connector with a JSM project URL
Providing Jira Cloud credentials (email + API token) or Server/DC PAT
Indexing service requests, incidents, problems, and changes

Closes #2281

Summary by cubic

Adds a Jira Service Management connector as a thin subclass of the Jira connector to index service requests, incidents, problems, and changes while reusing Jira auth, JQL, and UI. Includes JSM-specific permission sync and prefixing so groups and docs are tagged with jira_service_management. Closes #2281.

New Features
- Added JiraServiceManagementConnector (uses jira_service_management_base_url) with DocumentSource.JIRA_SERVICE_MANAGEMENT; registered in backend mapping and UI with form (incl. scoped_token), credential defaults, auto-sync, and Admin title.
- Introduced subclass hooks: JiraConnector.document_source, process_jira_issue(source); permission helpers accept source for correct group prefixing.
- Added JSM-specific doc_sync and group_sync that instantiate the JSM connector and read jira_service_management_base_url; wired in EE sync_params.
Bug Fixes
- Permission prefixing now threads the connector document_source through Jira access and EE page access, so JSM groups/docs use jira_service_management.
- Extracted public jira_group_sync_impl shared by Jira/JSM; JSM syncs read explicit config keys and use the JIRA_CONNECTOR_LABELS_TO_SKIP fallback; corrected JSM docs link to /jira_service_management; added missing scoped_token to the JSM TS interface.

^{Written for commit 50d12a9497f6ae1e4a8932da778e73efe8d29836. Summary will update on new commits.}