Add sixth sequential asset expansion batch

docs/asset-backlog.md

@@ -6,9 +6,9 @@ generated, connected, validated, built, flow-tested, committed, and pushed.
 
 ## Current Baseline
 
-- Story images: 76 files after Batch 5.
-- Portraits: 38 files after Batch 5.
-- Unit sheets: 132 files, 66 complete base/action design pairs after Batch 5.
+- Story images: 88 files after Batch 6.
+- Portraits: 44 files after Batch 6.
+- Unit sheets: 142 files, 71 complete base/action design pairs after Batch 6.
 - Target direction:
   - Story: about 5 images per major campaign chapter across 65 campaign stages.
   - Portraits: one portrait for every important `scenario.ts` speaker.
@@ -192,3 +192,46 @@ late-campaign speakers, and strengthens low-variant unit families.
 - `unit-wei-officer-iron.png` + `unit-wei-officer-iron-actions.png`
 - `unit-wu-infantry-river.png` + `unit-wu-infantry-river-actions.png`
 - `unit-rebel-archer-veteran.png` + `unit-rebel-archer-veteran-actions.png`
+
+## Batch 6 Priority
+
+Status: complete. Visual contact sheets, image dimensions, unit base/action pairs,
+`pnpm build`, and `pnpm verify:flow` passed. `sun-qian-campaign.png` was
+regenerated once for clearer character differentiation. Code connection uses the
+existing story, portrait, and unit variant discovery paths.
+
+This batch expands mid-campaign and late northern-campaign story backgrounds,
+adds campaign variants for supporting speakers, and improves the lowest-count
+unit families.
+
+### Story
+
+- `77-xuzhou-gate-council.png`
+- `78-xuzhou-night-evacuation.png`
+- `79-anti-dong-coalition-council.png`
+- `80-anti-dong-night-assault.png`
+- `81-chengdu-surrender-court.png`
+- `82-chengdu-outer-gate-surrender.png`
+- `83-wudu-yinping-cloud-road.png`
+- `84-chencang-siege-fortress-standoff.png`
+- `85-chencang-siege-engineering-camp.png`
+- `86-weishui-camps-logistics.png`
+- `87-weishui-camps-night-alarm.png`
+- `88-lucheng-pursuit-valley-road.png`
+
+### Portraits
+
+- `mi-zhu-campaign.png`
+- `jian-yong-campaign.png`
+- `sun-qian-campaign.png`
+- `pang-tong-campaign.png`
+- `fa-zheng-campaign.png`
+- `meng-huo-campaign.png`
+
+### Units
+
+- `unit-wu-strategist-river.png` + `unit-wu-strategist-river-actions.png`
+- `unit-nanman-infantry-jungle.png` + `unit-nanman-infantry-jungle-actions.png`
+- `unit-rebel-cavalry-veteran.png` + `unit-rebel-cavalry-veteran-actions.png`
+- `unit-rebel-leader-warlord.png` + `unit-rebel-leader-warlord-actions.png`
+- `unit-shu-officer-council.png` + `unit-shu-officer-council-actions.png`