fix(jira): correct browse URL, rename Procedure to Proof of Concept; feat(tempo): debug endpoint + UI

Jira URL fix:
- JiraLinkPanel now fetches the configured Jira base URL via getJiraConfig()
  instead of hardcoding https://jira.atlassian.com; falls back to the old
  value if config is not yet loaded

Description fix:
- _build_test_description: renamed 'h3. Procedure' -> 'h3. Proof of Concept'
  so the procedure/tool block maps to the correct Jira field label

Tempo debug:
- New POST /system/tempo-test endpoint: checks TEMPO_ENABLED, token,
  user jira_account_id, and makes a real API call; always returns HTTP 200
  with status field (Cloudflare-safe)
- docker-compose.prod.yml: added TEMPO_ENABLED, TEMPO_API_TOKEN,
  TEMPO_DEFAULT_WORK_TYPE env vars (default off, ready to enable)
- SettingsPage: added 'Test Tempo Connection' button in Jira admin tab
  with clear feedback showing what's missing

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/services/jira_service.py

@@ -208,7 +208,7 @@ def _build_test_description(test: Test, technique: Optional[Technique]) -> str:
         "h3. Description",
         test.description or "_No description provided._",
         "",
-        "h3. Procedure",
+        "h3. Proof of Concept",
         f"{{code}}{test.procedure_text or 'N/A'}{{code}}",
         "",
         f"*Tool:* {test.tool_used or 'N/A'}",