fix(preview): keep rendered lines inside the window

[delphinus]

ContentBuilder wraps the text at max_width and prepends the indent afterwards, so a rendered line can be max_width + #indent wide. The window-sized renders set max_width to the window's usable width, which let lines run up to two columns past the right edge. 'wrap' then put their last one or two characters on a screen row of their own at column 0, so a wrapped list item looked as if its text had lost its hanging indent.

Which lines overflow depends on where the wrap points fall, so the float (80% of the screen) and the pager (full width) showed it on different lines.

The fix

A content_width(win, indent) helper takes the indent off the window width, and both places that size max_width from the window use it: Session:bind_window and the WinResized handler. The split, which renders with no indent, is unchanged.

When the float hits its 80% cap, the content now reaches the window's right edge instead of passing it, so that case has no right margin. Otherwise the float stays content width + 2.

Tests

Lines wider than the render window, before and after, rendering a document with a wrapped checkbox item and a wrapped nested item:

mode	before (40–90 columns)	after
float	1–4 lines at every width up to 90	none
pager	1–2 lines at 40, 50, 60	none
toggle	1–2 lines at 40, 50, 60	none
split	none	none

tests/content_width_test.lua is new: toggle, split and pager at 40, 51, 60 and 73 columns, checking that no line is wider than the window. 8 of its 12 cases fail without the fix. make test passes.

🤖 Generated with Claude Code