feat(missions): document reader + three-tab IA for the mission page

The mission page made its own output unreadable. Reviewing a research
brief meant scrolling a 300px <pre> nested inside a 260px run box nested
inside the page scroller (plus a 4th scroll region for the description) —
and the text was capped at 6,000 chars server-side with no way to fetch
the rest, so a 53kB brief showed ~11% of itself and silently dropped the
remainder. Eight flat tabs (overview/phases/tasks/team/live/artifacts/
benchmarks/pane) mixed lifecycle, work items, people, telemetry, outputs
and infra at one level, so nothing indicated where the deliverable lived.

Reader:
- GET /api/missions/{id}/documents lists every agent output (titles +
  sizes, no bodies); GET .../documents/{run_id}/{index} returns one in
  full. Scoped to the mission so a run id from elsewhere can't be read.
- MissionOutputReader: rail (documents grouped by phase) · document ·
  outline (headings, click to jump). Exactly one scroll container per
  column, never nested. Copy + download .md.
- MarkdownBlock gains fenced code blocks (agent output is full of ```rust,
  previously mangled into paragraphs), h4-h6, heading anchors, and an
  outlineOf() helper.

Information architecture:
- Three primary tabs with shallow sub-views: RUN (phases/tasks/live) ·
  OUTPUT (documents/artifacts/benchmarks) · SETUP (overview/team/pane).
- PhaseRunsList shows a short excerpt with no inner scrollbar and points
  at the reader for the full text.
- The header description is clipped, not scrollable; its full text now
  has a home in Setup → Overview.

Missions list:
- /api/missions returns MissionListItem — Mission flattened plus
  phases_total/phases_done/current_phase, so the JSON stays a strict
  superset. Cards render a progress bar and "Coding · 1/2" instead of a
  bare status dot.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

frontend/src/components/dashboard/MissionsList.tsx

@@ -11,8 +11,9 @@ import { Plus, RotateCw, Trash2, Wrench } from "lucide-react";
 import {
   deleteMission,
   listMissions,
-  type Mission,
+  type MissionListItem,
   type MissionStatus,
+  type PhaseKind,
   type TemplateKind,
 } from "@/lib/api/missions";
 import { MissionWizard } from "./MissionWizard";
@@ -52,7 +53,7 @@ export function MissionsList({
    *  currently-open mission was among the deleted rows. */
   onDeleted?: (deletedIds: string[]) => void;
 }) {
-  const [missions, setMissions] = useState<Mission[]>([]);
+  const [missions, setMissions] = useState<MissionListItem[]>([]);
   const [loading, setLoading] = useState(true);
   const [wizardOpen, setWizardOpen] = useState(false);
   const [error, setError] = useState<string | null>(null);
@@ -351,6 +352,49 @@ export function MissionsList({
                 >
                   {m.title}
                 </div>
+                {/* Where the mission actually IS. A status dot alone
+                    doesn't distinguish "just launched" from "nearly done". */}
+                {m.phases_total > 0 && (
+                  <div
+                    style={{
+                      display: "flex",
+                      alignItems: "center",
+                      gap: 6,
+                      marginTop: 2,
+                    }}
+                  >
+                    <div
+                      style={{
+                        flex: 1,
+                        height: 3,
+                        borderRadius: 2,
+                        background: "rgba(255,255,255,.08)",
+                        overflow: "hidden",
+                      }}
+                    >
+                      <div
+                        style={{
+                          width: `${Math.round((m.phases_done / m.phases_total) * 100)}%`,
+                          height: "100%",
+                          background: STATUS_COLOR[m.status],
+                        }}
+                      />
+                    </div>
+                    <span
+                      style={{
+                        fontFamily: mono,
+                        fontSize: 9,
+                        color: "#6a6a72",
+                        flex: "none",
+                      }}
+                    >
+                      {m.current_phase
+                        ? `${PHASE_LABEL[m.current_phase] ?? m.current_phase} · `
+                        : ""}
+                      {m.phases_done}/{m.phases_total}
+                    </span>
+                  </div>
+                )}
               </button>
             );
           })
@@ -371,6 +415,13 @@ export function MissionsList({
   );
 }
 
+const PHASE_LABEL: Record<PhaseKind, string> = {
+  research: "Research",
+  coding: "Coding",
+  benchmark: "Benchmark",
+  security_scan: "Security",
+};
+
 const iconBtn: React.CSSProperties = {
   width: 26,
   height: 26,