Pr/develop to 5fa3703 fix: multiple bug fixes, security hardening, Docker improvements and MCP enhancements

[wchy1128]

Fix: HTTP status code not updated after JS challenge

• async_crawler_strategy.py: Added same-domain document response tracking (_js_nav_status). When the initial goto
  returns 403/503 but a JS challenge triggers a same-domain navigation with the real status code, the final status is
  automatically corrected. Resolves crawl failures on sites like Zhihu.

Unify verbose configuration strategy

• async_configs.py: Changed BrowserConfig.verbose and CrawlerRunConfig.verbose defaults from True to False to reduce
  noisy logs.
• cli.py: Fixed verbose priority to CLI --verbose flag > global config > default (False).
• config.py: Added DB_VERBOSE config option to independently control database logging.
• async_database.py: Database logger verbose now reads from ~/.crawl4ai/global.yml (DB_VERBOSE).
• async_webcrawler.py: When verbose is enabled, prints full BrowserConfig/CrawlerRunConfig and anti-bot block reasons.
• Tests: Updated test_verbose_default_false to match the new default.

Fix: MCP ask node schema returning empty

• Fixed the schema definition for the MCP ask endpoint.

MCP nodes support full config passthrough

• mcp_bridge.py: All MCP nodes now uniformly accept BrowserConfig and CrawlerRunConfig parameters. Improved config
  loading logic.

Add MCP ask node parameter constraints

• Enhanced schema definitions with parameter constraint descriptions.

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Docker Deployment Changes (deploy/docker/)

New custom image build pipeline

• Added Dockerfile.custom: Builds on the official image, pulls code from a GitHub fork — no local files needed.
• Added build-custom-image.sh: Convenience build script supporting repo/branch/tag/base-image arguments.
• Removed old Dockerfile.patch (manual patching no longer needed).

Improved debug playground + new result preview page

• server.py: Added /playground2 route for viewing crawled HTML/Markdown results.
• playground/index.html: Improved debug playground with --verbose and --json-ensure-ascii config options; fixed
  innerHTML causing extra link loading.
• playground2/index.html: New result preview page (~1300 lines) for real-time crawl result inspection.

Fix: Regex deprecation warning

• Fixed Python regex deprecation warnings on startup.

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Total: 17 files changed, +1740 / -141 lines. Main focus: JS challenge status code fix, verbose config overhaul, Docker
custom image build, debug/preview page enhancements.

Test plan

• Verify Docker build and playground pages work
• Confirm MCP endpoints handle browser/crawler configs correctly
• Run regression test suite (c4ai-check passed)