feat: Agent Orchestrator — multi-project agent dashboard

Tauri + Svelte 5 + Rust application for orchestrating multiple AI coding agents.
Includes Claude, Aider, Codex, and Ollama provider support, multi-agent
communication (btmsg/bttask), session anchors, plugin sandbox, FTS5 search,
Landlock sandboxing, and 507 vitest + 110 cargo tests.

src-tauri/src/session/metrics.rs

@@ -0,0 +1,80 @@
+// Session metrics persistence (session_metrics table)
+
+use rusqlite::params;
+use serde::{Deserialize, Serialize};
+use super::SessionDb;
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct SessionMetric {
+    #[serde(default)]
+    pub id: i64,
+    pub project_id: String,
+    pub session_id: String,
+    pub start_time: i64,
+    pub end_time: i64,
+    pub peak_tokens: i64,
+    pub turn_count: i64,
+    pub tool_call_count: i64,
+    pub cost_usd: f64,
+    pub model: Option<String>,
+    pub status: String,
+    pub error_message: Option<String>,
+}
+
+impl SessionDb {
+    pub fn save_session_metric(&self, metric: &SessionMetric) -> Result<(), String> {
+        let conn = self.conn.lock().unwrap();
+        conn.execute(
+            "INSERT INTO session_metrics (project_id, session_id, start_time, end_time, peak_tokens, turn_count, tool_call_count, cost_usd, model, status, error_message) VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9, ?10, ?11)",
+            params![
+                metric.project_id,
+                metric.session_id,
+                metric.start_time,
+                metric.end_time,
+                metric.peak_tokens,
+                metric.turn_count,
+                metric.tool_call_count,
+                metric.cost_usd,
+                metric.model,
+                metric.status,
+                metric.error_message,
+            ],
+        ).map_err(|e| format!("Save session metric failed: {e}"))?;
+
+        // Enforce retention: keep last 100 per project
+        conn.execute(
+            "DELETE FROM session_metrics WHERE project_id = ?1 AND id NOT IN (SELECT id FROM session_metrics WHERE project_id = ?1 ORDER BY end_time DESC LIMIT 100)",
+            params![metric.project_id],
+        ).map_err(|e| format!("Prune session metrics failed: {e}"))?;
+
+        Ok(())
+    }
+
+    pub fn load_session_metrics(&self, project_id: &str, limit: i64) -> Result<Vec<SessionMetric>, String> {
+        let conn = self.conn.lock().unwrap();
+        let mut stmt = conn.prepare(
+            "SELECT id, project_id, session_id, start_time, end_time, peak_tokens, turn_count, tool_call_count, cost_usd, model, status, error_message FROM session_metrics WHERE project_id = ?1 ORDER BY end_time DESC LIMIT ?2"
+        ).map_err(|e| format!("Query prepare failed: {e}"))?;
+
+        let metrics = stmt.query_map(params![project_id, limit], |row| {
+            Ok(SessionMetric {
+                id: row.get(0)?,
+                project_id: row.get(1)?,
+                session_id: row.get(2)?,
+                start_time: row.get(3)?,
+                end_time: row.get(4)?,
+                peak_tokens: row.get(5)?,
+                turn_count: row.get(6)?,
+                tool_call_count: row.get(7)?,
+                cost_usd: row.get(8)?,
+                model: row.get(9)?,
+                status: row.get(10)?,
+                error_message: row.get(11)?,
+            })
+        }).map_err(|e| format!("Query failed: {e}"))?
+        .collect::<Result<Vec<_>, _>>()
+        .map_err(|e| format!("Row read failed: {e}"))?;
+
+        Ok(metrics)
+    }
+}