Sync advanced search fields from query changes

[keilogic]

Fixes #755

Summary

• Pass the current search expression into the advanced search form so reopening the high-level search UI sees the latest query text.
• Parse the query shapes generated by the advanced search form back into the matching controls, including current-folder, sender/recipient/subject, all-fields text, attachment/reply/flag/unread flags, and date.
• Preserve raw/unstructured query text in the all-fields input instead of dropping it when the query does not match a structured field.

Testing

• Confirmed the new focused regression tests fail before the implementation:
  • npx ng test --include src/app/xapian/multiple-search-fields-input/multiple-search-fields-input.component.spec.ts --watch=false --browsers=FirefoxHeadless
  • Result on the test-only commit: TOTAL: 2 FAILED, 2 SUCCESS
• npx ng test --include src/app/xapian/multiple-search-fields-input/multiple-search-fields-input.component.spec.ts --watch=false --browsers=FirefoxHeadless
  • Result after the fix: TOTAL: 4 SUCCESS
• npx tsc -p src/tsconfig.app.json --noEmit
• npx tsc -p src/tsconfig.spec.json --noEmit
• npm run lint -- --quiet
• npm run policy
  • Passed; the output still lists existing historical upstream commit-message warnings, and the new commits pass the policy check.
• git diff --check origin/master...HEAD
• SKIP_CHANGELOG=1 production build sequence:
  • node src/build/pre-build.js
  • npx ng build runbox7 --configuration production --base-href=/app/
  • node src/build/post-build.js
  • Build hash: 5d484fa471e80dca
  • Passed with existing Angular/CommonJS/theming warnings.

AI Assistance

AI assistance used: OpenAI Codex in the local development workspace. The agent was used for code edits, tests, validation commands, commit splitting, and PR text preparation.