docs: update README for Linux support, Qdrant backend, and portable systemd unit

README.md

@@ -9,7 +9,7 @@
 <p align="center">
   <a href="LICENSE"><img src="https://img.shields.io/badge/license-MIT-blue.svg" alt="License: MIT"></a>
   <img src="https://img.shields.io/badge/python-3.11%20%7C%203.12-blue.svg" alt="Python 3.11 | 3.12">
-  <img src="https://img.shields.io/badge/platform-macOS-lightgrey.svg" alt="Platform: macOS">
+  <img src="https://img.shields.io/badge/platform-macOS%20%7C%20Linux-lightgrey.svg" alt="Platform: macOS | Linux">
 </p>
 <p align="center">
   <img src="https://img.shields.io/badge/verbatim%20recall-%E2%89%A599%25%20at%2010k-brightgreen.svg" alt="Verbatim recall >= 99%">
@@ -17,6 +17,7 @@
   <img src="https://img.shields.io/badge/encryption-AES--256--GCM-green.svg" alt="AES-256-GCM">
   <img src="https://img.shields.io/badge/local--only-no%20telemetry-green.svg" alt="Local only, no telemetry">
   <img src="https://img.shields.io/badge/MCP-compatible-purple.svg" alt="MCP compatible">
+  <img src="https://img.shields.io/badge/backend-LanceDB%20%7C%20Qdrant-blue.svg" alt="Backend: LanceDB | Qdrant">
 </p>
 
 ---
@@ -56,14 +57,12 @@ I built this for myself. It worked. I've been running it daily for months, and n
 
 ### Prerequisites
 
-- macOS (Apple Silicon tested)
+- macOS (Apple Silicon tested) or Linux
 - Python 3.11 or 3.12
 - Node.js 18+
 - [Claude Code](https://docs.claude.com/en/docs/claude-code/overview) as the MCP host
 - ~500 MB free disk
 
-Windows and Linux not supported yet but I'm working on it.
-
 ### Install
 
 ```bash
@@ -72,7 +71,7 @@ cd iai-mcp
 bash scripts/install.sh
 ```
 
-The installer creates a Python venv, installs dependencies (LanceDB, sentence-transformers, torch-hd, NetworkX, igraph), builds the TypeScript MCP wrapper, pre-downloads the default embedding model (~130 MB), symlinks the CLI to `~/.local/bin/iai-mcp`, and on macOS registers the daemon with launchd.
+The installer creates a Python venv at `~/.venv/iai-mcp`, installs dependencies (LanceDB, sentence-transformers, torch-hd, NetworkX, igraph), builds the TypeScript MCP wrapper, pre-downloads the default embedding model (~130 MB), symlinks the CLI to `~/.local/bin/iai-mcp`, and on macOS registers the daemon with launchd. On Linux, install the systemd unit from `deploy/systemd/iai-mcp-daemon.service`.
 
 Make sure `~/.local/bin` is on your `PATH`:
 
@@ -149,6 +148,21 @@ tail ~/.iai-mcp/logs/capture-$(date -u +%Y-%m-%d).log
 
 You should see a `rc=0` line. That's your first memory.
 
+### Linux (systemd)
+
+Install the systemd user unit:
+
+```bash
+mkdir -p ~/.config/systemd/user
+cp deploy/systemd/iai-mcp-daemon.service ~/.config/systemd/user/
+systemctl --user daemon-reload
+systemctl --user enable --now iai-mcp-daemon.service
+```
+
+For survival past logout (headless servers): `loginctl enable-linger $USER`
+
+Check status: `systemctl --user status iai-mcp-daemon.service`
+
 ---
 
 ## Usage
@@ -185,8 +199,14 @@ All records are encrypted at rest with AES-256-GCM. The key lives in `~/.iai-mcp
 
 Everything lives at `~/.iai-mcp/`. Embeddings are computed locally with `bge-small-en-v1.5`. The only data that leaves the machine is your normal conversation with whatever LLM API your client uses.
 
+### Storage backends
+
+The default backend is **LanceDB** (embedded, zero-config, local). For larger deployments or multi-machine setups, an optional **Qdrant** backend is available. Set `QDRANT_URL` to enable it — the system auto-selects the backend via a factory function.
+
+Migrate from LanceDB to Qdrant: `iai-mcp migrate qdrant`
+
 ```
-Claude Code  <--MCP-stdio-->  TypeScript wrapper  <--UNIX socket-->  Python daemon  <-->  LanceDB
+Claude Code  <--MCP-stdio-->  TypeScript wrapper  <--UNIX socket-->  Python daemon  <-->  LanceDB / Qdrant
 ```
 
 ---
@@ -224,9 +244,19 @@ The LongMemEval-S run is blind on purpose. No dataset-specific tuning, no hyperp
 |---|---|---|
 | `IAI_MCP_STORE` | `~/.iai-mcp/` | Data directory |
 | `IAI_MCP_EMBED_MODEL` | `bge-small-en-v1.5` | Embedding model. `bge-m3` for multilingual at ~3x size. |
+| `QDRANT_URL` | _(unset)_ | Qdrant server URL. When set, uses Qdrant backend instead of LanceDB. |
+| `QDRANT_API_KEY` | _(unset)_ | Qdrant API key |
 
 Switching embedders requires re-embedding the store: `iai-mcp migrate reembed`.
 
+### Non-AVX CPUs
+
+If your CPU lacks AVX support, rebuild the venv with the CPU-only PyTorch wheel:
+
+```bash
+bash scripts/rebuild-venv.sh
+```
+
 ---
 
 ## Doctor
@@ -302,7 +332,7 @@ Claude Desktop should work (uses `claude_desktop_config.json` instead of `~/.cla
 
 Other MCP-over-stdio hosts speak the same protocol and should work in principle. Not tested.
 
-If you get it running on something else, open an issue or PR.
+Linux support via systemd is available. macOS via launchd.
 
 ---
 

deploy/systemd/iai-mcp-daemon.service

@@ -16,7 +16,7 @@ After=default.target
 
 [Service]
 Type=simple
-ExecStart=/home/andreas/.venv/iai-mcp/bin/python -m iai_mcp.daemon
+ExecStart=%h/.venv/iai-mcp/bin/python -m iai_mcp.daemon
 Restart=on-failure
 RestartSec=30
 StartLimitIntervalSec=60