deny: operator can attach a reason that reaches the manager

clicking DENY on the dashboard now prompts for an optional reason
('reason for denying (optional, sent to manager):'). the value
rides along as a hidden 'note' form field; backend chain:

  POST /deny/{id} { note }
    → actions::deny(coord, id, Some(note))
    → Approvals::mark_denied writes it to the row
    → HelperEvent::ApprovalResolved { ..., note: Some("...") }

manager already had note: Option<String> on the event, just never
populated for denials before. host admin socket (hive-c0re deny)
still passes None.

generalized the prompt-on-submit pattern: any form with a
data-prompt attribute pops a window.prompt() before the POST and
stashes the answer in a hidden input named by data-prompt-field
(default 'note'). reusable for future opt-in note fields.

TODO.md

@@ -44,15 +44,6 @@ Pick anything from here when relevant. Cross-cutting design notes live in
 
 ## UI / UX
 
-- **Dashboard: show per-agent applied config.** Surface
-  `/var/lib/hyperhive/applied/<name>/agent.nix` (the file the
-  container actually builds from) as a collapsible `<details>`
-  block on each container row, alongside the journald viewer.
-  Backend: new `GET /api/agent-config/{name}` returns the file
-  contents (text/plain). Frontend: lazy-fetch on expand, render
-  inside a `<pre>` with the same theming as the journal panel.
-  Useful for spot-checking what `request_apply_commit` produced
-  without ssh-ing in.
 - **xterm.js terminal** embedded per-agent, attached to a PTY exposed by
   the harness. Pairs well with the unprivileged-container work — would let
   the operator drop into the container without `nixos-container root-login`.

hive-c0re/assets/app.js

@@ -164,6 +164,21 @@
     if (!(f instanceof HTMLFormElement) || !f.hasAttribute('data-async')) return;
     e.preventDefault();
     if (f.dataset.confirm && !confirm(f.dataset.confirm)) return;
+    if (f.dataset.prompt) {
+      const ans = prompt(f.dataset.prompt, '');
+      if (ans === null) return;  // operator hit Cancel
+      // Drop into a hidden input named after `data-prompt-field` (or
+      // 'note' by default) so the value rides along on the POST.
+      const field = f.dataset.promptField || 'note';
+      let input = f.querySelector(`input[name="${field}"]`);
+      if (!input) {
+        input = document.createElement('input');
+        input.type = 'hidden';
+        input.name = field;
+        f.append(input);
+      }
+      input.value = ans;
+    }
     const btn = f.querySelector('button[type="submit"], button:not([type]), .btn-inline');
     const original = btn ? btn.innerHTML : '';
     if (btn) { btn.disabled = true; btn.innerHTML = '<span class="spinner">◐</span>'; }
@@ -290,6 +305,9 @@
       // narrows to the harness service (or empty = full machine).
       const journalUnit = c.is_manager ? 'hive-m1nd.service' : 'hive-ag3nt.service';
       li.append(buildJournalDetails(c.container, journalUnit));
+      // Per-container applied config viewer. Shows the agent.nix
+      // the container is actually built against.
+      li.append(buildConfigDetails(c.name));
 
       ul.append(li);
     }
@@ -348,6 +366,48 @@
     return details;
   }
 
+  // Per-container applied-config viewer. Lazy-fetches on expand;
+  // refresh button re-fetches. Read-only — the file is hive-c0re's
+  // applied repo, mutated only via the approval flow.
+  function buildConfigDetails(agentName) {
+    const details = el('details', {
+      class: 'journal',
+      'data-restore-key': 'agent-config:' + agentName,
+    });
+    const summary = el('summary', {}, '↳ agent.nix · ' + agentName);
+    const body = el('div', { class: 'journal-body' });
+    const controls = el('div', { class: 'journal-controls' });
+    const refresh = el('button', { type: 'button', class: 'btn btn-restart journal-refresh' },
+      '↻ refresh');
+    const pre = el('pre', { class: 'journal-output' }, 'fetching…');
+    let fetching = false;
+    async function fetchConfig() {
+      if (fetching) return;
+      fetching = true;
+      pre.textContent = 'fetching…';
+      try {
+        const resp = await fetch('/api/agent-config/' + agentName);
+        const text = await resp.text();
+        if (!resp.ok) {
+          pre.textContent = 'error: ' + resp.status + '\n' + text;
+        } else {
+          pre.textContent = text || '(empty)';
+          pre.scrollTop = 0;
+        }
+      } catch (err) {
+        pre.textContent = 'fetch failed: ' + err;
+      } finally {
+        fetching = false;
+      }
+    }
+    details.addEventListener('toggle', () => { if (details.open) fetchConfig(); });
+    refresh.addEventListener('click', (e) => { e.preventDefault(); fetchConfig(); });
+    controls.append(refresh);
+    body.append(controls, pre);
+    details.append(summary, body);
+    return details;
+  }
+
   function renderTombstones(s) {
     const root = $('tombstones-section');
     root.innerHTML = '';
@@ -571,11 +631,21 @@
             'new sub-agent — container will be created on approve'),
         );
       }
+      // Deny prompts the operator for an optional reason; the
+      // submit handler stashes it into a hidden `note` input that
+      // rides along on the POST and is surfaced to the manager via
+      // HelperEvent::ApprovalResolved { note }.
+      const denyForm = el('form', {
+        method: 'POST', action: '/deny/' + a.id,
+        class: 'inline', 'data-async': '',
+        'data-prompt': 'reason for denying (optional, sent to manager):',
+      });
+      denyForm.append(el('button', { type: 'submit', class: 'btn btn-deny' }, 'DENY'));
       row.append(
         ' ',
         form('/approve/' + a.id, 'btn-approve', '◆ APPR0VE'),
         ' ',
-        form('/deny/' + a.id, 'btn-deny', 'DENY'),
+        denyForm,
       );
       li.append(row);
       if (a.diff_html) {

hive-c0re/src/actions.rs

@@ -178,17 +178,17 @@ pub async fn destroy(coord: &Coordinator, name: &str, purge: bool) -> Result<()>
     Ok(())
 }
 
-pub fn deny(coord: &Coordinator, id: i64) -> Result<()> {
+pub fn deny(coord: &Coordinator, id: i64, note: Option<&str>) -> Result<()> {
     let approval = coord.approvals.get(id)?;
-    coord.approvals.mark_denied(id)?;
-    tracing::info!(%id, "approval denied");
+    coord.approvals.mark_denied(id, note)?;
+    tracing::info!(%id, note, "approval denied");
     if let Some(a) = approval {
         coord.notify_manager(&HelperEvent::ApprovalResolved {
             id: a.id,
             agent: a.agent,
             commit_ref: a.commit_ref,
             status: ApprovalStatus::Denied,
-            note: None,
+            note: note.map(String::from),
         });
     }
     Ok(())

hive-c0re/src/approvals.rs

@@ -142,12 +142,12 @@ impl Approvals {
         })
     }
 
-    pub fn mark_denied(&self, id: i64) -> Result<()> {
+    pub fn mark_denied(&self, id: i64, note: Option<&str>) -> Result<()> {
         let conn = self.conn.lock().unwrap();
         let affected = conn.execute(
-            "UPDATE approvals SET status = 'denied', resolved_at = ?1
-               WHERE id = ?2 AND status = 'pending'",
-            params![now_unix(), id],
+            "UPDATE approvals SET status = 'denied', resolved_at = ?1, note = ?2
+               WHERE id = ?3 AND status = 'pending'",
+            params![now_unix(), note, id],
         )?;
         if affected == 0 {
             bail!("approval {id} not pending");

hive-c0re/src/dashboard.rs

@@ -54,6 +54,7 @@ pub async fn serve(port: u16, coord: Arc<Coordinator>) -> Result<()> {
         .route("/cancel-question/{id}", post(post_cancel_question))
         .route("/purge-tombstone/{name}", post(post_purge_tombstone))
         .route("/api/journal/{name}", get(get_journal))
+        .route("/api/agent-config/{name}", get(get_agent_config))
         .route("/request-spawn", post(post_request_spawn))
         .route("/messages/stream", get(messages_stream))
         .with_state(AppState { coord });
@@ -409,8 +410,23 @@ async fn post_approve(State(state): State<AppState>, AxumPath(id): AxumPath<i64>
     }
 }
 
-async fn post_deny(State(state): State<AppState>, AxumPath(id): AxumPath<i64>) -> Response {
-    match actions::deny(&state.coord, id) {
+#[derive(Deserialize, Default)]
+struct DenyForm {
+    #[serde(default)]
+    note: Option<String>,
+}
+
+async fn post_deny(
+    State(state): State<AppState>,
+    AxumPath(id): AxumPath<i64>,
+    Form(form): Form<DenyForm>,
+) -> Response {
+    let note = form
+        .note
+        .as_deref()
+        .map(str::trim)
+        .filter(|s| !s.is_empty());
+    match actions::deny(&state.coord, id, note) {
         Ok(()) => Redirect::to("/").into_response(),
         Err(e) => error_response(&format!("deny {id} failed: {e:#}")),
     }
@@ -548,6 +564,30 @@ async fn get_journal(
     }
 }
 
+/// Show the current `agent.nix` from the applied repo — the file
+/// the container actually builds against. Read-only; the manager
+/// can't influence what this returns (that path goes through the
+/// approval queue).
+async fn get_agent_config(AxumPath(name): AxumPath<String>) -> Response {
+    let logical = strip_container_prefix(&name);
+    // Constrain to managed containers — same shape as the journal
+    // endpoint, prevents arbitrary filesystem reads.
+    let live = lifecycle::list().await.unwrap_or_default();
+    let prefixed = if logical == lifecycle::MANAGER_NAME {
+        logical.clone()
+    } else {
+        format!("{}{logical}", lifecycle::AGENT_PREFIX)
+    };
+    if !live.iter().any(|c| c == &prefixed) {
+        return error_response(&format!("agent-config: no managed container {prefixed:?}"));
+    }
+    let path = Coordinator::agent_applied_dir(&logical).join("agent.nix");
+    match std::fs::read_to_string(&path) {
+        Ok(body) => ([("content-type", "text/plain; charset=utf-8")], body).into_response(),
+        Err(e) => error_response(&format!("read {}: {e}", path.display())),
+    }
+}
+
 async fn post_purge_tombstone(
     State(state): State<AppState>,
     AxumPath(name): AxumPath<String>,

hive-c0re/src/server.rs

@@ -144,7 +144,7 @@ async fn dispatch(req: &HostRequest, coord: Arc<Coordinator>) -> HostResponse {
                 HostResponse::success()
             }
             HostRequest::Deny { id } => {
-                actions::deny(&coord, *id)?;
+                actions::deny(&coord, *id, None)?;
                 HostResponse::success()
             }
         })