Rework Tasks tab: Chains section, checklist modal, project visibility

The flat Tasks-tab atom list was silently dumping every chain step
(locked and unlocked) and dormant bucket-pool items in as ordinary
undated cards, with no chain/project context and no protection against
completing a locked step out of order.

- CompleteNativeTask now rejects completing a locked chain task
  (ErrChainTaskLocked), mapped to 400 in both the widget and web
  complete-atom handlers.
- Chain tasks and dormant bucket items are excluded from the flat atom
  list; a new "Chains" section shows one card per active/paused chain
  with the current step and N/M progress.
- New chain checklist modal (GET /chains/{id}) lists every position in
  order with pause/resume/abandon -- the web view originally deferred
  as Android-only.
- Fixed a real bug this surfaced: resuming a paused chain only flipped
  the status flag, never unlocking the deferred successor, so a chain
  paused right after a completion stayed stuck forever. SetChainStatus
  now catches up the deferred advancement on resume, idempotently.
- Atom cards gained a project-name chip for general visibility.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EZ7ikw2ukGJFTHE3bJS7zL

1 files changed, 17 insertions, 0 deletions

diff --git a/web/templates/index.html b/web/templates/index.html
index 19f1c7e..7be2c52 100644
--- a/web/templates/index.html
+++ b/web/templates/index.html
@@ -262,11 +262,15 @@
             if (e.key === 'Escape') {
                 closeActionModal();
                 closeTaskModal();
+                closeChainModal();
             }
         });
         function closeTaskModal() {
             document.getElementById('task-edit-modal').classList.add('hidden');
         }
+        function closeChainModal() {
+            document.getElementById('chain-view-modal').classList.add('hidden');
+        }
     </script>
 
     <!-- Task Edit Modal -->
@@ -282,6 +286,19 @@
         </div>
     </div>
 
+    <!-- Chain Checklist Modal -->
+    <div id="chain-view-modal" class="hidden fixed inset-0 bg-modal-overlay flex items-center justify-center p-4 z-50">
+        <div class="bg-modal backdrop-blur-sm rounded-lg max-w-lg w-full max-h-[80vh] flex flex-col" style="box-shadow: 0 0 20px black;">
+            <div class="p-4 border-b border-white/10 flex justify-between items-center flex-shrink-0">
+                <h2 class="font-medium text-white">Chain</h2>
+                <button onclick="closeChainModal()" class="text-white/40 hover:text-white">✕</button>
+            </div>
+            <div id="chain-view-content" class="overflow-y-auto">
+                <p class="p-4 text-white/50 text-sm">Loading...</p>
+            </div>
+        </div>
+    </div>
+
     <div class="fixed bottom-0 right-0 p-2 text-[10px] text-white/20 pointer-events-none">
         {{.BuildVersion}}
     </div>