file viewer, docs, ws: add image/media preview path, projects doc, ws wiring

Show file gains image and video display for capable agents. Docs add
projects.md and update index. Wire ws file-watch in project-board.
Minor fs tool and CLAUDE.md updates.

docs/index.md

@@ -4,7 +4,13 @@ This folder is written for **you, the assistant**, not for the human directly. I
 
 Keep answers grounded in what's actually enabled and configured for this instance — check with the relevant tool (e.g. list installed/enabled plugins) rather than assuming everything described here is turned on. A feature documented here may not be enabled on this particular instance.
 
-This index will grow over time. Right now it covers plugins; more sections (agents, connectors, memory, security groups, shared folders, projects…) will be added later.
+This index will grow over time. Right now it covers projects and plugins; more sections (agents, connectors, memory, security groups, shared folders…) will be added later.
+
+## Features
+
+| Document | What it covers |
+| --- | --- |
+| [projects.md](projects.md) | Projects: shared folders with their own assistant chat, a live file explorer, and member sharing |
 
 ## Plugins