Align GTK app with Apple home surface

Add the GTK home screen, local account store, daemon gRPC wrapper, and embedded Linux daemon startup path so the Linux app follows the Apple client UX and daemon boundary.

Document the GTK parity expectations and update the daemon IPC and Tailnet BEPs with the cross-platform client model.

burrow-gtk/src/account_store.rs

@@ -0,0 +1,139 @@
+use anyhow::{Context, Result};
+use serde::{Deserialize, Serialize};
+use std::{
+    path::PathBuf,
+    time::{SystemTime, UNIX_EPOCH},
+};
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct AccountRecord {
+    pub id: String,
+    pub kind: AccountKind,
+    pub title: String,
+    pub authority: Option<String>,
+    pub account: String,
+    pub identity: String,
+    pub hostname: Option<String>,
+    pub tailnet: Option<String>,
+    pub note: Option<String>,
+    pub created_at: u64,
+    pub updated_at: u64,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "lowercase")]
+pub enum AccountKind {
+    WireGuard,
+    Tor,
+    Tailnet,
+}
+
+impl AccountKind {
+    pub fn title(self) -> &'static str {
+        match self {
+            Self::WireGuard => "WireGuard",
+            Self::Tor => "Tor",
+            Self::Tailnet => "Tailnet",
+        }
+    }
+
+    fn sort_rank(self) -> u8 {
+        match self {
+            Self::Tailnet => 0,
+            Self::Tor => 1,
+            Self::WireGuard => 2,
+        }
+    }
+}
+
+pub fn load() -> Result<Vec<AccountRecord>> {
+    let path = storage_path()?;
+    if !path.exists() {
+        return Ok(Vec::new());
+    }
+    let data =
+        std::fs::read(&path).with_context(|| format!("failed to read {}", path.display()))?;
+    serde_json::from_slice(&data).with_context(|| format!("failed to parse {}", path.display()))
+}
+
+pub fn upsert(mut record: AccountRecord) -> Result<Vec<AccountRecord>> {
+    let mut accounts = load()?;
+    let now = timestamp();
+    record.updated_at = now;
+    if record.created_at == 0 {
+        record.created_at = now;
+    }
+
+    if let Some(index) = accounts.iter().position(|account| account.id == record.id) {
+        accounts[index] = record;
+    } else {
+        accounts.push(record);
+    }
+    accounts.sort_by(|lhs, rhs| {
+        lhs.kind
+            .sort_rank()
+            .cmp(&rhs.kind.sort_rank())
+            .then_with(|| lhs.title.to_lowercase().cmp(&rhs.title.to_lowercase()))
+    });
+    persist(&accounts)?;
+    Ok(accounts)
+}
+
+pub fn new_record(
+    kind: AccountKind,
+    title: String,
+    authority: Option<String>,
+    account: String,
+    identity: String,
+    hostname: Option<String>,
+    tailnet: Option<String>,
+    note: Option<String>,
+) -> AccountRecord {
+    let now = timestamp();
+    AccountRecord {
+        id: format!("{}-{now}", kind.title().to_ascii_lowercase()),
+        kind,
+        title,
+        authority,
+        account,
+        identity,
+        hostname,
+        tailnet,
+        note,
+        created_at: now,
+        updated_at: now,
+    }
+}
+
+fn persist(accounts: &[AccountRecord]) -> Result<()> {
+    let path = storage_path()?;
+    if let Some(parent) = path.parent() {
+        std::fs::create_dir_all(parent)
+            .with_context(|| format!("failed to create {}", parent.display()))?;
+    }
+    let data = serde_json::to_vec_pretty(accounts).context("failed to encode account store")?;
+    std::fs::write(&path, data).with_context(|| format!("failed to write {}", path.display()))
+}
+
+fn storage_path() -> Result<PathBuf> {
+    if let Some(data_home) = std::env::var_os("XDG_DATA_HOME") {
+        return Ok(PathBuf::from(data_home)
+            .join("burrow")
+            .join("accounts.json"));
+    }
+    if let Some(home) = std::env::var_os("HOME") {
+        return Ok(PathBuf::from(home)
+            .join(".local")
+            .join("share")
+            .join("burrow")
+            .join("accounts.json"));
+    }
+    Ok(std::env::temp_dir().join("burrow-accounts.json"))
+}
+
+fn timestamp() -> u64 {
+    SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .map(|duration| duration.as_secs())
+        .unwrap_or_default()
+}