feat(settings): improve navigation and configuration search

[openai0229]

Related issue

Closes #2266

Summary

• Reorganize settings navigation and page content into clearer groups with responsive layouts and the requested product/Lucide icon treatment.
• Add shared settings search with Cmd/Ctrl+F focus, exact-control navigation, centered scrolling, selected-result and target highlighting, shortcut-group expansion, and filtering of unavailable conditional controls.
• Simplify the About view, add contextual help for unfamiliar editor options, and add focused navigation, search, layout, localization, and accessibility contract coverage to CI.

Affected surfaces

• Frontend / Web
• Backend / API / Storage
• Database plugin / Driver
• JCEF / Desktop packaging
• CI / Build / Release
• Documentation only

Verification

• Commands and results:
  • yarn test:settings-layout - passed
  • yarn lint - passed with zero warnings
  • yarn test:i18n - passed for all validated frontend modules, properties bundles, and READMEs
  • yarn build:web:community --app_version=5.3.0 - compiled successfully
• Manual verification: Iterative local review covered navigation hierarchy, editor grouping, search-result selection, exact-control highlighting, and the simplified About view.
• UI evidence: N/A - reviewed in the local application during implementation; no screenshot artifact is attached.

Risk and compatibility

• Public API or stored data: N/A - no API, schema, or persisted setting keys changed.
• Database or driver compatibility: N/A - no database or driver behavior changed.
• Network, privacy, or security: Existing proxy behavior and credential handling are unchanged; only settings presentation and discoverability changed.
• Community / Local / Pro boundary: The shared shell supports each existing menu profile, while runtime edition flags continue to gate MCP, proxy, account, license, and device entries.
• Backward compatibility: Existing setting values and actions are preserved; the change is limited to layout, navigation, help text, and search behavior.

Reviewer map

• Start here: chat2db-community-client/src/blocks/Setting/SettingLayout.tsx, then search.ts, searchCatalog.ts, and EditorSetting/index.tsx.
• Failure condition: A result opens the wrong page, cannot reveal/highlight its exact visible control, exposes a hidden conditional control, or an edition-specific menu loses an existing destination.
• Rollback or disable path: Revert commit 29f48e76; no data migration or cleanup is required.

Contributor declaration

• I linked the Issue that defines this change.
• I tested the affected behavior and reported the actual results above.
• I did not include credentials, private data, or generated build output.
• I disclosed substantial AI assistance below, or this PR contains no substantial AI-generated code.

AI assistance: OpenAI Codex provided substantial implementation, test-authoring, and review assistance. The maintainer supplied the requirements and performed iterative local visual review.