doc: document lobby conversation structure very important

doc/README.md

@@ -232,6 +232,34 @@ so, it doesn't seem like there's a particular flag that identifies maiden races,
 - card_talent_upgrade has costs to increase potential level, but it doesn't seem to have skill sets
 - card_talent_hint_upgrade has costs to raise hint levels, but it's actually universal, only six rows
 - single_mode_route_race is career goals (not only races)
+- available_skill_set has starting skills including those unlocked by potential level given under need_rank (0 for pl1, 2 for pl2)
+
+# lobby conversations!!!
+
+table is home_story_trigger.
+
+pos_id values:
+- 110 right side, toward the front
+- 120 same, but two characters
+- 130 same, but three characters
+- 210 left side table
+- 220
+- 310 center back seat
+- 410 center posters
+- 420
+- 430
+- 510 left school map
+- 520
+- 530
+
+num is how many characters are involved, but also can just check chara_id_{1,2,3} for nonzero.
+
+unsure what condition_type is.
+values of 2 and 3 always have two or three characters, and values of 4 (jp only) always have three, but 0 and 1 can have any number.
+
+gallery_chara_id is the character whose conversation it is; chara_id_{1,2,3} are the characters involved.
+gallery_chara_id is always one of the three, but it can be any one of the three.
+disp_order then is the conversation number within their gallery.
 
 # update diffs