[COLLABORATION] Add topic-scoped documents and context via upload or link from drive #3089

Area: Topic context. Phase: 2.

Outcome

Owners drop files into a topic; the topic keeps them, and the agent in any of the topic's chats can list and read them.

Today

No topic file storage. Uploads go into a single room only.

Scope

• Topic file store: upload, list, delete, download; owner-scoped; size limits.
• Storage location decided here. Leading option: base SEMOSS storage provider under collaboration/topic///, so configured cloud storage gives long-term persistence.
• Agent tools ListTopicFiles and ReadTopicFile, plus copy-into-room.
• Merge moves files; delete removes them; archive keeps them.

Acceptance

• A file uploaded to a topic is readable by the agent in every chat of that topic and none outside it.
• Files survive a server restart and redeploy.

Size and dependencies

• Size: M
• Depends on: [COLLABORATION] Link chats to topics #3110

Proposed data shape

BRAIN_TOPIC_FILE(OWNER_ID, OWNER_TYPE, FILE_ID, TOPIC_ID, NAME, PATH, SIZE, MIME, UPLOADED_AT) plus the bytes in the chosen store.

Code pointers

• src/prerna/engine/api/IStorageEngine.java and engine/impl/storage/AbstractRCloneStorageEngine.java (storage engines)
• src/prerna/cluster/util/ClusterUtil.java (how room/project assets already persist to cloud storage; see engine/impl/model/Room.java)
• src/prerna/collaboration/BrainAttachments.java (size-limit pattern, COLLAB_ATTACHMENT_MAX_MB)
• src/prerna/collaboration/CollaborationAgentTools.java (new tools)

Related work

Companion: SEMOSS/semoss-ui#3709. Depends on #3110.

Open decisions

Storage provider and path.

How to verify

Through the local Monolith + Tomcat + UI loop (fixture mail mode for repeatable cases), then on the pilot pod. Do not add Semoss/test JUnit tests.