feat(web): DB-backed Jobs tab + scheduler-dispatched local jobs (#436)

* feat(web): DB-backed Jobs tab, scheduler-dispatched local jobs, remove active-jobs-bar

- Remove active-jobs-bar UI element (HTML, CSS, JS polling)
- Move job handlers from server.rs to handlers/jobs.rs
- Remove user_id scoping (single-user gateway)
- Add list_agent_jobs() and agent_job_summary() to Database trait
  (both postgres and libsql backends) for non-sandbox job visibility
- Wire SchedulerSlot into CreateJobTool so execute_local dispatches
  via scheduler (persists to DB + spawns worker) instead of creating
  phantom ContextManager-only jobs
- Update /status and /list slash commands to read from DB for
  consistency with Jobs tab
- Fix worker mark_completed: skip if already terminal or stuck
- Add agent job cancel via DB update in both web handler and slash cmd
- Add Stuck → Completed guard with tracing in worker completion path

Co-Authored-By: Claude Sonnet 4.6 <[email protected]>

* fix: address PR review comments

- Log warning when get_context fails in worker completion path
- Extract duplicated status-counting logic into AgentJobSummary::add_count()
  helper, used by both postgres and libsql backends

Co-Authored-By: Claude Sonnet 4.6 <[email protected]>

---------

Co-authored-by: Claude Sonnet 4.6 <[email protected]>
Co-authored-by: Nick Pismenkov <[email protected]>

src/history/mod.rs

@@ -14,6 +14,6 @@ pub use analytics::{JobStats, ToolStats};
 #[cfg(feature = "postgres")]
 pub use store::Store;
 pub use store::{
-    ConversationMessage, ConversationSummary, JobEventRecord, LlmCallRecord, SandboxJobRecord,
-    SandboxJobSummary, SettingRow,
+    AgentJobRecord, AgentJobSummary, ConversationMessage, ConversationSummary, JobEventRecord,
+    LlmCallRecord, SandboxJobRecord, SandboxJobSummary, SettingRow,
 };

src/history/store.rs

@@ -487,6 +487,45 @@ pub struct SandboxJobSummary {
     pub interrupted: usize,
 }
 
+/// Lightweight record for agent (non-sandbox) jobs, used by the web Jobs tab.
+#[derive(Debug, Clone)]
+pub struct AgentJobRecord {
+    pub id: Uuid,
+    pub title: String,
+    pub status: String,
+    pub user_id: String,
+    pub created_at: DateTime<Utc>,
+    pub started_at: Option<DateTime<Utc>>,
+    pub completed_at: Option<DateTime<Utc>>,
+    pub failure_reason: Option<String>,
+}
+
+/// Summary counts for agent (non-sandbox) jobs.
+#[derive(Debug, Clone, Default)]
+pub struct AgentJobSummary {
+    pub total: usize,
+    pub pending: usize,
+    pub in_progress: usize,
+    pub completed: usize,
+    pub failed: usize,
+    pub stuck: usize,
+}
+
+impl AgentJobSummary {
+    /// Accumulate a status/count pair into the summary buckets.
+    pub fn add_count(&mut self, status: &str, count: usize) {
+        self.total += count;
+        match status {
+            "pending" => self.pending += count,
+            "in_progress" => self.in_progress += count,
+            "completed" | "submitted" | "accepted" => self.completed += count,
+            "failed" | "cancelled" => self.failed += count,
+            "stuck" => self.stuck += count,
+            _ => {}
+        }
+    }
+}
+
 #[cfg(feature = "postgres")]
 impl Store {
     /// Insert a new sandbox job into `agent_jobs`.
@@ -754,6 +793,55 @@ impl Store {
         }
         Ok(summary)
     }
+
+    /// List all agent (non-sandbox) jobs, most recent first.
+    pub async fn list_agent_jobs(&self) -> Result<Vec<AgentJobRecord>, DatabaseError> {
+        let conn = self.conn().await?;
+        let rows = conn
+            .query(
+                r#"
+                SELECT id, title, status, user_id, failure_reason,
+                       created_at, started_at, completed_at
+                FROM agent_jobs WHERE source = 'direct'
+                ORDER BY created_at DESC
+                "#,
+                &[],
+            )
+            .await?;
+
+        Ok(rows
+            .iter()
+            .map(|r| AgentJobRecord {
+                id: r.get("id"),
+                title: r.get("title"),
+                status: r.get("status"),
+                user_id: r.get::<_, Option<String>>("user_id").unwrap_or_default(),
+                created_at: r.get("created_at"),
+                started_at: r.get("started_at"),
+                completed_at: r.get("completed_at"),
+                failure_reason: r.get("failure_reason"),
+            })
+            .collect())
+    }
+
+    /// Summary counts for agent (non-sandbox) jobs.
+    pub async fn agent_job_summary(&self) -> Result<AgentJobSummary, DatabaseError> {
+        let conn = self.conn().await?;
+        let rows = conn
+            .query(
+                "SELECT status, COUNT(*) as cnt FROM agent_jobs WHERE source = 'direct' GROUP BY status",
+                &[],
+            )
+            .await?;
+
+        let mut summary = AgentJobSummary::default();
+        for row in &rows {
+            let status: String = row.get("status");
+            let count: i64 = row.get("cnt");
+            summary.add_count(&status, count as usize);
+        }
+        Ok(summary)
+    }
 }
 
 // ==================== Job Events ====================