fix(ui): refine workspace tabs and navigation

[openai0229]

Related issue

Closes #2351
Closes #2352
Closes #2355

Summary

• Show only the file name in local SQL file workspace tabs while preserving the absolute path for file operations.
• Use Lucide MessageSquarePlus for conversations and LayoutDashboard for Dashboard.
• Give the static Output tab a compact fixed width of 96 px while keeping query-result tabs at 200 px.

Affected surfaces

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

Verification

• Commands and results: yarn lint:eslint passed; yarn test:local-file-tab-title passed; yarn test:result-tab-preferences passed; yarn test:search-result-tab-selection passed; git diff --check passed.
• Manual verification: Started Community backend on 10825, main-checkout frontend on 8889, and the local JCEF preview against http://127.0.0.1:8889; webpack connected and the workspace rendered.
• UI evidence: Verified in the local JCEF preview; the requester confirmed the combined result looks correct.

Risk and compatibility

• Public API or stored data: N/A; frontend display changes only.
• Database or driver compatibility: N/A.
• Network, privacy, or security: N/A.
• Community / Local / Pro boundary: Changes are scoped to the Community frontend.
• Backward compatibility: Existing absolute file paths and query-result tab widths are preserved.

Reviewer map

• Start here: chat2db-community-client/src/blocks/SearchResult/index.tsx, chat2db-community-client/src/pages/main/CommunityMainPage.tsx, and chat2db-community-client/src/pages/main/workspace/utils/localTextFile.ts.
• Failure condition: Output tabs remain 200 px, navigation shows the previous icons, or local file tabs expose absolute paths.
• Rollback or disable path: Revert the three commits in this PR.

Contributor declaration

• I linked the Issues that define 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.

AI assistance: Codex assisted with implementation, tests, runtime startup, and PR consolidation.