Improve character speech bubble tail placement

Right now the speech bubble tail is in the middle of the right edge of the bubble.

With a longer text, the tail is far away from the player character graphic.

It would be nice if the tail was always in the same place, or at least next to the player character's head.

No file, entry point, or test is named in the issue. Start by locating the speech-bubble rendering and the player-character graphic, then reproduce the behavior with longer dialogue text; done means the tail remains near the character's head rather than drifting toward the middle of the bubble edge.

Written by the indexing model from the issue text.