Answer budget within the context window; enforced reviews of completed todos

Context window
- Requests asked for the model's full max_output, but providers count
  input + output against the window: long chats with large-output models
  (DeepSeek V4.1 Flash, 384k) failed with "input too long" before automatic
  compaction (85 %) kicked in. max_tokens is now what the window leaves
  (estimated input = last usage + messages since), the chat is compacted when
  less than 32k would remain for an answer, and a context-overflow error
  compacts and retries once.
- ModelConfig.max_input (catalogue limit.input, editable in the provider
  settings) lowers the compaction threshold for models with an input limit.

Enforced reviews (modes with refine.rounds > 0, refine.after_todos default on)
- Every todo marked completed is reviewed against the work since the last
  review; with findings it is reopened and the feedback goes to the agent
  (max. rounds per todo). Passed reviews leave a visible note.
- Ending the turn with open todos sends the agent back to work while it makes
  progress (max. 10 reminders in a row without progress); such modes may take
  up to 2,000 steps per turn. Reaching the step limit is reported.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/src/styles.css

@@ -1068,6 +1068,13 @@ button.session-group:hover {
 .form label {
   color: var(--fg2);
 }
+.form label.check {
+  grid-column: 2;
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  color: var(--fg1);
+}
 .form .hint {
   grid-column: 2;
   font-size: 12px;
@@ -3164,6 +3171,28 @@ button.danger-solid {
 .refine-card summary .icon {
   color: var(--purple);
 }
+.harness-note {
+  display: flex;
+  align-items: baseline;
+  gap: 8px;
+  margin: 6px 0;
+  padding: 6px 10px;
+  border-left: 3px solid var(--blue);
+  border-radius: 4px;
+  background: var(--bg1);
+  font-size: 12.5px;
+  color: var(--fg2);
+}
+.harness-note .icon {
+  color: var(--blue);
+  flex-shrink: 0;
+}
+.harness-note.ok {
+  border-left-color: var(--green);
+}
+.harness-note.ok .icon {
+  color: var(--green);
+}
 
 /* --- automations ---------------------------------------------------------------- */
 .job.off {