chore: point the Atlassian MCP server at the Streamable HTTP endpoint

The HTTP+SSE endpoint (mcp.atlassian.com/v1/sse) is deprecated after 2026-06-30.
Switch to the Streamable HTTP transport (type: http, /v1/mcp).

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: balzss

.mcp.json

@@ -1,8 +1,8 @@
 {
   "mcpServers": {
     "atlassian": {
-      "type": "sse",
-      "url": "https://mcp.atlassian.com/v1/sse"
+      "type": "http",
+      "url": "https://mcp.atlassian.com/v1/mcp"
     },
     "slack": {
       "command": "sh",