docs: describe the joint chart and deck search approach in the roadmap

docs/roadmap.en.md

@@ -8,6 +8,7 @@ Only unfinished work is listed; finished items are removed.
 
 - Exact proofs within a time budget on every objective and scene: tighter interior bounds on Gekisou charts, cheaper exact leaf evaluation (performance orders sharing their common start), and initial decks from a fast heuristic.
 - Tighter bounds on Gekisou charts (bonus bounds on combo charts).
+- Tighter Maximum node bounds from distinct characters: the other terms' bonuses keyed by the characters already placed, and the gain column and spread envelope taken over unused characters only.
 
 ## Gekisou rank parameter
 
@@ -51,4 +52,13 @@ Requirements:
 - Results identify both chart and team; the same team on different charts gives distinct results. The global canonical order is explicit and keeps the within-chart tie contract; PT is still computed per performance order before averaging.
 - The outer search may prioritize charts with prepared data and admissible request-specific upper bounds, but never truncates charts by a static song ranking or the best score seen so far. The inner search shares the global cutoff only through a proven lower-bound contract; an unfinished inner incumbent is a feasible proposal, not a certificate.
 - Global Complete requires every admitted chart domain to be exhausted or excluded by an admissible bound that also preserves secondary ranking and canonical ties. Timeout, unsupported input, numeric/capacity failure and an unfinished chart stay explicit, with the remaining chart domains and their certificate state.
+Approach:
+
+- One branch-and-bound whose first branching variable is the chart: each chart first gets an admissible root upper bound over its whole team domain (every skill effect bounded as the search already bounds it, no search), charts are expanded best-first by that bound, and there is one global (chart, team) Top-K.
+- A chart whose root bound is below the global K-th is excluded whole; a remaining chart's inner search only has to prove that no team beats the global K-th (a threshold search), not its own Top-K.
+- The card pool and power tables are shared across charts; good teams found on one chart seed the others.
+- An entry point that compiles the bounds and returns the root bound only, covering Gekisou, PT and partitioned searches.
+- Bounds of event-point, challenge-point and item objectives follow each chart's score bound; when the reward saturates, the threshold search ranks by the secondary order such as power.
+- The winning combinations are always scored by a complete replay.
+
 - Validation: exhaustive joint chart/deck oracles on bounded fixtures, fixed-deck cross-chart comparison, charts with different missions/bonuses/rank thresholds, canonical ties, and native/WASM comparisons.

docs/roadmap.md

@@ -8,6 +8,7 @@
 
 - 所有目标和场景在时间预算内给出精确证明：撃奏谱的中间层上界继续收紧、叶子精确评估降本（出场顺序共享相同的开头）、由快速启发式提供初始卡组。
 - 撃奏谱的上界继续收紧（连击谱的加成）。
+- Maximum 聚合的节点上界按“五人角色互异”收紧：其他项的加成按已放角色取值，增益列与分差包络只取未用角色。
 
 ## 撃奏名次参数
 
@@ -51,4 +52,13 @@
 - 结果同时标识谱面和队伍，同一队伍在不同谱面上是不同的结果。全局规范顺序要明确，并保留谱面内的平局约定；PT 仍按每个出场顺序先算再平均。
 - 外层可以优先有预备数据和可采纳上界的谱面，但不能用静态歌曲排名或目前最好分截断谱面。内层只能通过已证明的下界契约共享全局截止值，未完成的内层结果只是可行解，不是证明。
 - 全局 Complete 要求每个纳入的谱面域都穷尽，或被同时保留次级排序与规范平局的可采纳上界排除。超时、不支持的输入、数值或容量失败、未完成的谱面都要明确报告剩余的谱面域及其证明状态。
+做法：
+
+- 一次分支定界，第一层按谱面分支：每张谱面先给出整个队伍域的可采纳根上界（所有技能效果按现有上界计入，不搜索），按上界从高到低展开；全局只有一份（谱面，队伍）Top-K。
+- 根上界低于全局第 K 名的谱面整张排除；未排除的谱面，内层只需证明没有队伍超过全局第 K 名（门槛搜索），不必求自己的 Top-K。
+- 卡池与综合力表跨谱面共用；一张谱面上找到的好队伍作为其他谱面的初始卡组。
+- 提供只编译上界、只给出根上界的入口，覆盖撃奏、PT 与分段搜索的谱面。
+- 活动 PT、CP、道具这类目标的上界要随谱面的分数上界变化；奖励饱和时按综合力等次级排序做门槛搜索。
+- 获胜的组合一律完整重放算分。
+
 - 验证：有界夹具上的谱面＋编成联合穷举对拍、固定编成的跨谱面对照、任务／加成／评级阈值不同的谱面、规范平局，以及本机与 WASM 对照。