Add HDFS browser, SSH terminal, presentation editor, lab health panel

- HDFS WebHDFS file browser (api/hdfs_api.py + HdfsView)
- In-browser SSH terminal via paramiko WebSocket bridge (api/ssh_terminal.py + SshTerminal, xterm.js)
- Presentation deck editor (text + image upload) and CRUD endpoints
- Collapsible GPU matrix + new LabHealthPanel in SideNav
- Topology fixes (edge alignment, Hadoop node, compact nodes)
- nginx ws timeout bump for long-lived SSH sessions

api/main.py

@@ -13,7 +13,7 @@ from typing import Any
 
 import httpx
 import redis.asyncio as aioredis
-from fastapi import FastAPI, File, UploadFile, WebSocket, WebSocketDisconnect
+from fastapi import Body, FastAPI, File, UploadFile, WebSocket, WebSocketDisconnect
 from fastapi.middleware.cors import CORSMiddleware
 from agent_terminal import (
     get_all_terminals,
@@ -25,11 +25,22 @@ from agent_terminal import (
 )
 from lab_context import collect_full_lab_context, format_context_for_agent
 from presentation import build_presentation_payload, render_presentation_html
-from presentation_upload import get_deck, list_decks, save_upload
+from presentation_upload import (
+    create_deck,
+    delete_deck,
+    get_asset_path,
+    get_deck,
+    list_decks,
+    save_deck,
+    save_image,
+    save_upload,
+)
 from presentation_static import get_static_deck, list_static_decks
 from storage_s3 import router as storage_s3_router
+from hdfs_api import router as hdfs_router
 from elasticsearch_api import router as elasticsearch_router
 from sql_console import router as sql_router
+from ssh_terminal import ssh_session
 from node_registry import NODE_IDS, NODE_AGENT, NODE_REGISTRY, is_node_id
 from node_ops import build_node_detail, probe_node, run_node_probe_task
 from approval_service import (
@@ -707,6 +718,7 @@ async def lifespan(app: FastAPI):
 
 app = FastAPI(title="ATC Command Center API", lifespan=lifespan)
 app.include_router(storage_s3_router)
+app.include_router(hdfs_router)
 app.include_router(elasticsearch_router)
 app.include_router(sql_router)
 app.add_middleware(
@@ -814,6 +826,67 @@ async def upload_presentation(file: UploadFile = File(...)):
     deck = await save_upload(file.filename or "upload.pptx", content)
     return {"ok": True, "deck": deck}
 
+
+@app.post("/api/presentation/decks/new")
+async def create_presentation_deck(body: dict[str, Any] | None = Body(default=None)):
+    body = body or {}
+    title = str(body.get("title") or "Untitled deck")
+    seed_id = body.get("from")
+    slides = None
+    if seed_id:
+        src = get_static_deck(seed_id) or get_deck(seed_id)
+        if seed_id == "live":
+            src = await get_presentation_data()
+        if src and src.get("slides"):
+            slides = [
+                {
+                    "id": s.get("id") or f"slide-{i}",
+                    "title": s.get("title") or f"Slide {i}",
+                    "subtitle": s.get("subtitle") or "",
+                    "bullets": list(s.get("bullets") or []),
+                    "image": s.get("image") or "",
+                    "kind": s.get("kind") or "narrative",
+                }
+                for i, s in enumerate(src["slides"], start=1)
+            ]
+            if not title or title == "Untitled deck":
+                title = f"{src.get('title', 'Deck')} (copy)"
+    deck = create_deck(title, slides)
+    return {"ok": True, "deck": deck}
+
+
+@app.put("/api/presentation/decks/{deck_id}")
+async def update_presentation_deck(deck_id: str, body: dict[str, Any] = Body(...)):
+    deck = save_deck(deck_id, body)
+    if not deck:
+        return {"error": "deck not found or not editable"}
+    return {"ok": True, "deck": deck}
+
+
+@app.delete("/api/presentation/decks/{deck_id}")
+async def remove_presentation_deck(deck_id: str):
+    return {"ok": delete_deck(deck_id)}
+
+
+@app.post("/api/presentation/decks/{deck_id}/image")
+async def upload_presentation_image(deck_id: str, file: UploadFile = File(...)):
+    content = await file.read()
+    if len(content) > 12 * 1024 * 1024:
+        return {"error": "image too large (max 12MB)"}
+    result = save_image(deck_id, file.filename or "image.png", content)
+    if not result:
+        return {"error": "deck not found"}
+    return {"ok": True, **result}
+
+
+@app.get("/api/presentation/decks/{deck_id}/assets/{name}")
+async def get_presentation_asset(deck_id: str, name: str):
+    from fastapi.responses import FileResponse, Response
+    path = get_asset_path(deck_id, name)
+    if not path:
+        return Response(status_code=404)
+    return FileResponse(str(path))
+
 @app.get("/api/workload")
 async def get_workload(fast: bool = True):
     return await collect_workload(fast=fast, use_cache=True)
@@ -1004,6 +1077,11 @@ async def post_prompt(body: PromptRequest):
     return {"prompt_id": prompt_id, "agent_id": agent_id, "status": "dispatched"}
 
 
+@app.websocket("/api/ws/ssh")
+async def ws_ssh(websocket: WebSocket):
+    await ssh_session(websocket)
+
+
 @app.websocket("/api/ws/ops")
 async def ws_ops(websocket: WebSocket):
     await websocket.accept()