chore: bump version to 0.2.0 + add CHANGELOG

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

CHANGELOG.md

@@ -0,0 +1,37 @@
+# Changelog
+
+## v0.2.0 — 2026-04-27
+
+### Fixed
+
+- **Setup wizard could silently overwrite an existing vault.** Pointing the
+  wizard at a remote that already contained a relicario vault would clobber
+  `manifest.enc`, `.relicario/salt`, and friends with no warning. The wizard
+  now probes the remote after the connection test and refuses to create a
+  new vault on top of an existing one. Affected users whose vault was wiped
+  by this bug should restore from the git history of the affected repo
+  (`git log` + `git checkout <pre-init-sha> -- .`).
+- **New devices registered during initial setup were silently dropped.** The
+  wizard's Step 5 fired `add_device` over a service-worker channel that
+  required an unlocked vault, which is unavailable mid-wizard. Device pubkeys
+  now write directly to `.relicario/devices.json` from the wizard.
+- **Wizard-created vaults were missing `settings.enc`.** The CLI's `init`
+  writes a default-`VaultSettings` `settings.enc` alongside `manifest.enc`,
+  but the wizard skipped it, causing every `get_vault_settings` SW call to
+  404. The wizard now encrypts and writes `settings.enc` using a new
+  `default_vault_settings_json` WASM helper that keeps defaults in sync
+  with Rust core.
+
+### Added
+
+- **Attach this device to an existing vault — purely from the GUI.** New
+  Step 0 mode picker splits the wizard into "create new vault" and "attach
+  this device." The attach path takes a passphrase + reference image, fetches
+  the existing manifest, verifies the credentials by decrypting it, and only
+  then registers a new device key. No CLI required for multi-device setup.
+- `GitHost.lastCommit(path)` and `GitHost.writeFileCreateOnly(path, ...)`.
+- `default_vault_settings_json()` WASM export.
+
+## v0.1.0 — 2026-04-22
+
+Initial release.