Fechamento de Caixa - Tauri 2 initial commit

- Storage: SQLite local via rusqlite
- Supabase: REST API via reqwest
- Printer: USB ESC/POS for TM-T20
- Frontend: vanilla HTML (form-v9.3 ported)
- Build: GitHub Actions for Linux/Windows/macOS

src-tauri/src/plugins/escpos.rs

@@ -0,0 +1,95 @@
+//! Comandos ESC/POS para impressoras térmicas 80mm
+//! Comandos Epson ESC/POS padrão — funciona com TM-T20 e compatíveis.
+
+/// Inicializar impressora
+pub const INIT: &[u8] = b"\x1B\x40";
+/// Nova linha
+pub const LF: &[u8] = b"\x0A";
+/// Cortar papel (parcial)
+pub const CUT: &[u8] = b"\x1D\x56\x01";
+/// Cortar papel (total)
+pub const CUT_FULL: &[u8] = b"\x1D\x56\x00";
+/// Alimentar 3 linhas antes de cortar
+pub const FEED_CUT: &[u8] = b"\x1B\x64\x03";
+/// Negrito ON / OFF
+pub const BOLD_ON: &[u8] = b"\x1B\x45\x01";
+pub const BOLD_OFF: &[u8] = b"\x1B\x45\x00";
+/// Alinhamento
+pub const ALIGN_LEFT: &[u8] = b"\x1B\x61\x00";
+pub const ALIGN_CENTER: &[u8] = b"\x1B\x61\x01";
+pub const ALIGN_RIGHT: &[u8] = b"\x1B\x61\x02";
+/// Fonte normal / dupla
+pub const FONT_NORMAL: &[u8] = b"\x1B\x21\x00";
+pub const FONT_DOUBLE: &[u8] = b"\x1B\x21\x30";
+/// Linha divisória (48 colunas para 80mm)
+pub const DIVIDER: &str = "--------------------------------";
+
+/// Monta texto centralizado com negrito + fonte dupla
+pub fn title(text: &str) -> Vec<u8> {
+    let mut out = Vec::new();
+    out.extend_from_slice(ALIGN_CENTER);
+    out.extend_from_slice(BOLD_ON);
+    out.extend_from_slice(FONT_DOUBLE);
+    out.extend_from_slice(text.as_bytes());
+    out.extend_from_slice(LF);
+    out.extend_from_slice(FONT_NORMAL);
+    out.extend_from_slice(BOLD_OFF);
+    out
+}
+
+/// Monta linha normal (alinhada à esquerda)
+pub fn line(text: &str) -> Vec<u8> {
+    let mut out = Vec::new();
+    out.extend_from_slice(ALIGN_LEFT);
+    out.extend_from_slice(text.as_bytes());
+    out.extend_from_slice(LF);
+    out
+}
+
+/// Monta linha centralizada
+pub fn line_center(text: &str) -> Vec<u8> {
+    let mut out = Vec::new();
+    out.extend_from_slice(ALIGN_CENTER);
+    out.extend_from_slice(text.as_bytes());
+    out.extend_from_slice(LF);
+    out
+}
+
+/// Monta linha em negrito
+pub fn line_bold(text: &str) -> Vec<u8> {
+    let mut out = Vec::new();
+    out.extend_from_slice(BOLD_ON);
+    out.extend_from_slice(ALIGN_LEFT);
+    out.extend_from_slice(text.as_bytes());
+    out.extend_from_slice(LF);
+    out.extend_from_slice(BOLD_OFF);
+    out
+}
+
+/// Monta linha com chave-valor alinhado (label 14 chars + espaço + valor 14 chars)
+pub fn kv(label: &str, value: &str) -> Vec<u8> {
+    let padded_label = format!("{:<14}", label);
+    let padded_value = format!("{:>14}", value);
+    let line = format!("{} {}", padded_label, padded_value);
+    let line = if line.len() > 48 { line[..48].to_string() } else { line };
+    let mut out = Vec::new();
+    out.extend_from_slice(ALIGN_LEFT);
+    out.extend_from_slice(line.as_bytes());
+    out.extend_from_slice(LF);
+    out
+}
+
+/// Monta linha divisória
+pub fn divider() -> Vec<u8> {
+    let mut out = Vec::new();
+    out.extend_from_slice(ALIGN_LEFT);
+    out.extend_from_slice(DIVIDER.as_bytes());
+    out.extend_from_slice(LF);
+    out
+}
+
+/// Monta espaço em branco (N linhas)
+pub fn blank_lines(n: u8) -> &'static [u8] {
+    const BLANK: &[u8] = b"\n\n\n\n\n\n\n\n";
+    &BLANK[..(n as usize).min(8)]
+}