fix(ai): restore table mention suggestions

[openai0229]

Related issue

N/A - fixes the Community AI mention regression.

Summary

Community AI @ suggestions now contain only database tables and views. The popup opens on explicit @ input, supports keyboard and mouse selection, protects against stale table/view responses, keeps the type column fixed on the right, and ellipsizes long names with a native title. AI datasource selection exposes only groups, data sources, databases, and schemas; monitor, user, and account nodes are excluded.

Affected surfaces

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

Verification

• yarn lint:eslint passed
• yarn test:retired-ai passed
• yarn build:web:community --app_version=0.0.0 passed, including production bundle verification
• Maven clean package for all 48 Community modules passed
• Focused backend tests passed
• Playwright CLI against http://127.0.0.1:8899 with backend http://127.0.0.1:10835 verified @, keyboard Enter, mouse selection, Escape/delete close, datasource filtering, fixed type column, title tooltip, and table/view requests only
• Source scan found no Community knowledge or context-reference markers

Risk and compatibility

• Community chat requests and history no longer expose knowledge-selection or context-reference fields.
• Existing unknown history fields remain ignored during deserialization.
• Table/view mentions and attachments remain available.

Reviewer map

• Start here: chat2db-community-client/src/blocks/AI/components/AIChatInput/index.tsx and chat2db-community-server/chat2db-community-web/src/main/java/ai/chat2db/community/web/api/adapter/ai/AiChatStreamAdapter.java
• Failure condition: @ suggestions do not open, select stale results, or expose non-table nodes.

Contributor declaration

• I tested the affected behavior and reported the actual results above.
• I did not include credentials, private data, or generated build output.

AI assistance: Codex traced the regression, removed the Community knowledge/context surface, added focused tests, and performed build and interaction verification.

[openai0229]

Final code review completed on head 6d6dd590a84437ee0a130685bbc17337b2716216 after rebasing onto current main.

Review fixes included:

• ignore stale in-flight table/view responses after the mention query changes;
• make stored AI messages tolerate retired extension fields;
• restrict the AI datasource selector to groups, datasources, databases, and schemas, excluding monitor/account/object nodes without mutating the shared workspace tree;
• keep the table/view type in a fixed 36px trailing column and ellipsize long names while preserving the full native title.

Verification passed locally: yarn lint:eslint, yarn test:retired-ai, yarn build:web:community --app_version=0.0.0, and 14 focused Maven tests. Playwright against isolated real backend/frontend (10835/8899) covered bare and filtered mentions, keyboard/mouse selection, Escape/delete close, rapid query changes, datasource context filtering, fixed type-column geometry, long-name overflow, and network inspection with no knowledge endpoint calls.

No unresolved code-review findings remain.