feat(web): slash command autocomplete + /status /list + fix chat input locking (#404)

* feat(web): slash command autocomplete, /status /list /cancel, fix input locking

Backend:
- Add JobStatus, JobList, JobCancel Submission variants to submission.rs
- Parse /status [id], /progress [id], /list, /cancel <id> as control commands
- Dispatch to existing handle_check_status/handle_list_jobs/handle_cancel_job
  handlers via new process_job_status/process_job_list/process_job_cancel methods
- Add 4 parser tests (34 total, all passing)

Web UI:
- Add slash command autocomplete: type / in chat input to see all 18 commands
  with descriptions; arrow-key navigation, Tab/Enter to select, Escape to close
- Remove chat input locking: drop textarea.disabled + sendBtn.disabled so users
  can always type and send (including /interrupt while agent is processing)
- Remove quick-action toolbar buttons (↩↪⏸⊖🗑📋) added in previous session
- Remove dead #chat-status bar (min-height 28px black bar always visible when empty)

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

* refactor: address PR review comments

- Remove Submission::JobList variant; parse /list directly as
  JobStatus { job_id: None } (simpler, eliminates redundant enum
  variant, match arm, is_control branch, and wrapper function)
- Cache autocomplete matches in _slashMatches to avoid re-filtering
  SLASH_COMMANDS on every keydown while autocomplete is open

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

---------

Co-authored-by: Claude Sonnet 4.6 <[email protected]>
Co-authored-by: Pierre LE GUEN <[email protected]>

src/agent/agent_loop.rs

@@ -717,6 +717,13 @@ impl Agent {
             Submission::Heartbeat => self.process_heartbeat().await,
             Submission::Summarize => self.process_summarize(session, thread_id).await,
             Submission::Suggest => self.process_suggest(session, thread_id).await,
+            Submission::JobStatus { job_id } => {
+                self.process_job_status(&message.user_id, job_id.as_deref())
+                    .await
+            }
+            Submission::JobCancel { job_id } => {
+                self.process_job_cancel(&message.user_id, &job_id).await
+            }
             Submission::Quit => return Ok(None),
             Submission::SwitchThread { thread_id: target } => {
                 self.process_switch_thread(message, target).await

src/agent/commands.rs

@@ -220,6 +220,33 @@ impl Agent {
         }
     }
 
+    /// Show job status inline — either all jobs (no id) or a specific job.
+    pub(super) async fn process_job_status(
+        &self,
+        user_id: &str,
+        job_id: Option<&str>,
+    ) -> Result<SubmissionResult, Error> {
+        match self
+            .handle_check_status(user_id, job_id.map(|s| s.to_string()))
+            .await
+        {
+            Ok(text) => Ok(SubmissionResult::response(text)),
+            Err(e) => Ok(SubmissionResult::error(format!("Job status error: {}", e))),
+        }
+    }
+
+    /// Cancel a job by ID.
+    pub(super) async fn process_job_cancel(
+        &self,
+        user_id: &str,
+        job_id: &str,
+    ) -> Result<SubmissionResult, Error> {
+        match self.handle_cancel_job(user_id, job_id).await {
+            Ok(text) => Ok(SubmissionResult::response(text)),
+            Err(e) => Ok(SubmissionResult::error(format!("Cancel error: {}", e))),
+        }
+    }
+
     /// Trigger a manual heartbeat check.
     pub(super) async fn process_heartbeat(&self) -> Result<SubmissionResult, Error> {
         let Some(workspace) = self.workspace() else {

src/agent/submission.rs

@@ -107,6 +107,29 @@ impl SubmissionParser {
             return Submission::Quit;
         }
 
+        // Job commands
+        if lower == "/status" || lower == "/progress" {
+            return Submission::JobStatus { job_id: None };
+        }
+        if let Some(rest) = lower
+            .strip_prefix("/status ")
+            .or_else(|| lower.strip_prefix("/progress "))
+        {
+            let id = rest.trim().to_string();
+            if !id.is_empty() {
+                return Submission::JobStatus { job_id: Some(id) };
+            }
+        }
+        if lower == "/list" {
+            return Submission::JobStatus { job_id: None };
+        }
+        if let Some(rest) = lower.strip_prefix("/cancel ") {
+            let id = rest.trim().to_string();
+            if !id.is_empty() {
+                return Submission::JobCancel { job_id: id };
+            }
+        }
+
         // /thread <uuid> - switch thread
         if let Some(rest) = lower.strip_prefix("/thread ") {
             let rest = rest.trim();
@@ -229,6 +252,18 @@ pub enum Submission {
     /// Suggest next steps based on the current thread.
     Suggest,
 
+    /// Check job status. No job_id shows all jobs; with job_id shows a specific job.
+    JobStatus {
+        /// Optional job ID (UUID or short prefix). If None, shows all jobs.
+        job_id: Option<String>,
+    },
+
+    /// Cancel a running job.
+    JobCancel {
+        /// Job ID (UUID or short prefix).
+        job_id: String,
+    },
+
     /// Quit the agent. Bypasses thread-state checks.
     Quit,
 
@@ -313,6 +348,8 @@ impl Submission {
                 | Self::Heartbeat
                 | Self::Summarize
                 | Self::Suggest
+                | Self::JobStatus { .. }
+                | Self::JobCancel { .. }
                 | Self::SystemCommand { .. }
         )
     }
@@ -740,6 +777,56 @@ mod tests {
         );
     }
 
+    #[test]
+    fn test_parser_job_status() {
+        // /status with no id → all jobs
+        let s = SubmissionParser::parse("/status");
+        assert!(matches!(s, Submission::JobStatus { job_id: None }));
+
+        // /progress alias
+        let s = SubmissionParser::parse("/progress");
+        assert!(matches!(s, Submission::JobStatus { job_id: None }));
+
+        // /status with id
+        let s = SubmissionParser::parse("/status abc123");
+        assert!(matches!(s, Submission::JobStatus { job_id: Some(id) } if id == "abc123"));
+
+        // /progress with id
+        let s = SubmissionParser::parse("/progress abc123");
+        assert!(matches!(s, Submission::JobStatus { job_id: Some(id) } if id == "abc123"));
+
+        // case insensitive
+        let s = SubmissionParser::parse("/STATUS");
+        assert!(matches!(s, Submission::JobStatus { job_id: None }));
+    }
+
+    #[test]
+    fn test_parser_job_list() {
+        // /list is an alias for /status with no job_id
+        let s = SubmissionParser::parse("/list");
+        assert!(matches!(s, Submission::JobStatus { job_id: None }));
+
+        let s = SubmissionParser::parse("/LIST");
+        assert!(matches!(s, Submission::JobStatus { job_id: None }));
+    }
+
+    #[test]
+    fn test_parser_job_cancel() {
+        let s = SubmissionParser::parse("/cancel abc123");
+        assert!(matches!(s, Submission::JobCancel { job_id } if job_id == "abc123"));
+
+        // /cancel with no id → falls through to UserInput
+        let s = SubmissionParser::parse("/cancel");
+        assert!(matches!(s, Submission::UserInput { .. }));
+    }
+
+    #[test]
+    fn test_job_commands_are_control() {
+        assert!(SubmissionParser::parse("/status").is_control());
+        assert!(SubmissionParser::parse("/list").is_control());
+        assert!(SubmissionParser::parse("/cancel abc").is_control());
+    }
+
     #[test]
     fn test_parser_quit() {
         assert!(matches!(SubmissionParser::parse("/quit"), Submission::Quit));