feat(web): dedicated full-page log viewer + run lyra-web as a service

The inline log panel is cramped, especially on mobile. Add a standalone
mobile-first log page and serve the chat server under systemd like the dream
loop (the nohup process didn't survive cleanly).

- static/logs.html: full-page live log — level filter chips, text search,
  pause/resume with buffering, autoscroll toggle, color-coded levels, and the
  expandable "view full prompt" block (where the now-note is visible in context)
- server: GET /logs serves the page (FileResponse)
- index.html: "⛶ Full Log" button opens /logs in a new tab
- deploy/lyra-web.service: user service so the chat server is reboot-resilient

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lyra/web/server.py

@@ -15,7 +15,7 @@ import time
 from pathlib import Path
 
 from fastapi import FastAPI, Request
-from fastapi.responses import StreamingResponse
+from fastapi.responses import FileResponse, StreamingResponse
 from fastapi.staticfiles import StaticFiles
 
 from lyra import chat, logbus, memory, summary
@@ -110,6 +110,11 @@ def create_app() -> FastAPI:
             ],
         }
 
+    @app.get("/logs")
+    async def logs_page() -> FileResponse:
+        """Full-page, mobile-friendly live log viewer (separate from the chat UI)."""
+        return FileResponse(str(_STATIC / "logs.html"))
+
     @app.get("/stream/logs")
     async def stream_logs(request: Request) -> StreamingResponse:
         """Live activity feed: replay the recent buffer, then stream new events."""