Title#

feat: add conditionally-validated Bitbucket + Jira env blocks to config schema (BJ-4)

Problem#

The config schema had no entries for Atlassian (Bitbucket/Jira) env vars, so partial configs would boot silently and only fail at runtime. #544 requires fail-fast validation that mirrors the existing GITHUB_APP_ID conditional pattern.

Task / Link#

Closes #544

Changes#

• Added BITBUCKET_OAUTH_CLIENT_ID as optional trigger; CLIENT_SECRET, REFRESH_TOKEN, WORKSPACE become required when it is set (via Joi.when())
• Added BITBUCKET_REPO, BITBUCKET_BOT_USERNAME, BITBUCKET_WEBHOOK_SECRET as plain optional entries
• Added JIRA_OAUTH_CLIENT_ID as optional trigger; CLIENT_SECRET, REFRESH_TOKEN, SITE_URL, CLOUD_ID become required when it is set
• Added JIRA_PROJECT_KEY, JIRA_BOT_USERNAME, JIRA_WEBHOOK_SECRET as plain optional entries
• Extended config.schema.spec.ts with Bitbucket mode and Jira mode describe blocks (empty / partial-fail / complete-pass cases)
• Appended commented # --- Bitbucket (optional) --- and # --- Jira (optional) --- blocks to .env.example

Notes#

• Only CLIENT_ID triggers required-companion validation (matches GITHUB_APP_ID single-gateway pattern); setting only CLIENT_SECRET will not error — intentional design.
• *_REFRESH_TOKEN validated for presence only; format/length checks are out of scope for this wave.

Testing#

• npx jest config.schema.spec — 14 tests pass (empty / partial-fail / complete-pass for both Bitbucket and Jira modes)
• Lint clean (npm run lint)