feat: multi-device sync (push, pull, autosync); v0.3.0

Add three new CLI commands so a vault can follow Federico across machines via
a private git remote:

- icontext push   — stage, commit, push to origin (with gh-create hint when no remote)
- icontext pull   — rebase --autostash, surface conflicts cleanly
- icontext autosync start|stop|status — launchd on macOS, systemd --user on Linux,
                                        runs 'icontext push' every 60s

The user-prompt-submit hook now also pulls from origin in the background when a
remote is configured, so Claude Code sees fresh context from other devices.

Updates README with a Multi-device sync section, CHANGELOG with [0.3.0] entry,
and bumps version to 0.3.0 in pyproject.toml + cli.py. 89 tests pass.

Author: federicodeponte

CHANGELOG.md

@@ -4,6 +4,22 @@ All notable changes to iContext will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 
+## [0.3.0] - 2026-05-02
+
+### Added
+- **Multi-device sync.** Your vault now follows you across machines via a private git remote.
+  - `icontext push` — commit and push local changes to origin
+  - `icontext pull` — rebase against origin with autostash (last-writer-wins, surfaces conflicts)
+  - `icontext autosync start|stop|status` — background agent that runs `icontext push` every 60 seconds
+    - macOS: `launchd` at `~/Library/LaunchAgents/dev.icontext.autosync.plist`
+    - Linux: `systemd --user` timer at `~/.config/systemd/user/icontext-autosync.timer`
+- `user-prompt-submit` hook now pulls from origin in the background if a remote is configured, so Claude Code sees fresh context from other machines at the start of every prompt.
+- CLAUDE.md snippet references the multi-device sync workflow.
+- Tests for `push`, `pull`, and `autosync` (--help, no-origin hint, status reports not running on clean home).
+
+### Changed
+- Bumped version to 0.3.0.
+
 ## [0.2.1] - 2026-05-02
 
 ### Fixed

README.md

@@ -226,6 +226,50 @@ Optional:
 - `git-lfs` for binary assets (`brew install git-lfs`)
 - `GEMINI_API_KEY` only if you want the headless `icontext sync` fallback
 
+## Multi-device sync
+
+Same vault, every machine. iContext uses git on a private repo as the sync layer — no extra service, no daemon talking to a vendor.
+
+### Setup (3 steps)
+
+On your **primary machine**, push the vault to a private repo:
+
+```bash
+cd ~/context
+gh repo create <user>/context --private --source=. --push
+icontext autosync start          # commits + pushes every 60s
+```
+
+On every **other machine**, clone and start autosync:
+
+```bash
+gh repo clone <user>/context ~/context
+icontext autosync start
+```
+
+That's it. Edits made on machine A appear on machine B within ~60s of the next prompt (the `user-prompt-submit` hook also pulls in the background whenever you start a Claude Code prompt).
+
+### Commands
+
+| Command | What it does |
+|---|---|
+| `icontext push` | Commit local changes and push to origin |
+| `icontext pull` | Rebase against origin (autostashes in-flight changes) |
+| `icontext autosync start` | Install + start the 60s background agent |
+| `icontext autosync stop` | Stop and remove the agent |
+| `icontext autosync status` | Show running state and last sync time |
+
+### Conflict handling
+
+`icontext pull` runs `git pull --rebase --autostash`. Last writer wins. If two machines edit the same lines of the same file in the same minute, the rebase surfaces the conflict and prints the file paths — resolve manually with normal git tooling.
+
+In practice, conflicts are rare: profile files are append-mostly, and the 60s push window is shorter than typical edit cycles.
+
+### Implementation
+
+- macOS: `launchd` agent at `~/Library/LaunchAgents/dev.icontext.autosync.plist`. Logs at `~/Library/Logs/icontext.log`.
+- Linux: `systemd --user` timer at `~/.config/systemd/user/icontext-autosync.timer`. Logs via `journalctl --user -u icontext-autosync.service`.
+
 ## How icontext compares
 
 Common question: "isn't this just like X?"