Add jiraIssueCreate capability, schema, and parser to Jira manifest

[vpanc]

Summary

Adds the jiraIssueCreate capability schema, parser, and Jira manifest declaration with the optional issueCreateUrl form variable.

Related issues

• O11Y-1615

Solution

Extends the existing Jira Cloud integration with a jiraIssueCreate capability so LaunchDarkly products (e.g. Observability) can create Jira issues via the Forge app’s issue-create web trigger.

Changes

• Add jiraIssueCreate capability schema + response parser (issueKey, issueUrl, optional self)
• Wire the capability into schemas/base.json and regenerate manifest.schema.json / manifest.schema.d.ts
• Update integrations/jira/manifest.json with:
  • optional issueCreateUrl form variable
  • jiraIssueCreate.creationRequest (endpoint, HMAC via shared secret, JSON body template, response parser)

Expected behavior

When a subscription has issueCreateUrl + secret configured (populated by the Forge app), gonfalon can call the issue-create web trigger and parse the created issue identifiers from the response.

Additional context

Supporting work lives in:

• gonfalon: dispatcher + UI, o11y-jira-issue-create feature flag
• observability: GraphQL mutations
• jira-forge-integration: issue-create web trigger

Gonfalon’s current dispatcher reads issueCreateUrl / secret from subscription config and builds the request body in Go. The manifest capability defines the supported contract for that flow.