Fix #262

CHANGELOG.md

@@ -21,6 +21,25 @@ listed under a **Changed** or **Removed** heading.
   cell and style assertions. Every Rust block in it is compiled against the
   crate in CI, and the README shows the one-line install for Claude Code.
 
+### Fixed
+
+- **Custom tab stops are honoured: `HTS`, `TBC`, `CHT` and `CBT` do what
+  they say.** Stops were fixed at every eighth column — the backend's
+  hardcoded value — and all four escapes reached a dispatch table with no
+  entry for them and vanished, though `hts`, `tbc` and `cbt` are all in the
+  terminfo entry termlens hands every child. An application that laid a
+  table out by setting its own stops and tabbing between them drew every
+  column in the wrong place, and did it *silently*: the characters were all
+  present, so `contains` still passed and only a column assertion or a
+  whole-screen snapshot could catch it. The stop set now lives in the
+  sequence tracker beside the character sets, and the emulator rewrites each
+  motion as a `CHA` the backend does dispatch. Plain `\t` is rewritten too,
+  or the backend's eight and a custom stop would disagree the moment one was
+  set. `RIS` and `DECSTR` restore the every-eighth default; a resize extends
+  the set into its new columns with that same pattern and leaves the stops
+  it already had alone. `CBT` is also what `Shift-Tab` sends, so an
+  application echoing one now moves. (#262)
+
 ## [0.9.0] - 2026-09-05
 
 ### Added

README.md

@@ -270,6 +270,14 @@ design. termlens's position:
   ROMs, the other national sets — is acknowledged and reads as ASCII.
   `DECSC`/`DECRC` save and restore this state with the cursor. Locking
   shifts remain G0/G1 only (`LS2`/`LS3` are not modelled).
+- **Tab stops are the application's to set.** `HTS` (`ESC H`), `TBC`
+  (`CSI g`, `CSI 3 g`), `CHT` (`CSI I`) and `CBT` (`CSI Z`) all work, and a
+  plain `\t` honours whatever stops are set rather than a fixed eight.
+  `RIS` and `DECSTR` restore the every-eighth default, and a resize extends
+  the set into its new columns with that pattern while leaving existing
+  stops alone. Back-tab moves to the nearest stop *strictly* left of the
+  cursor, as xterm does. Only `TBC 0` and `TBC 3` are modelled; the rest of
+  that family clears *line* tab stops, which this crate has no notion of.
 - `wait_frame` needs the application to bracket its repaints in DEC 2026
   synchronized updates, and only the last 8 completed frames are retained;
   everything else waits with `wait_until`, under the three rules in