Can no longer `isearch-yank-word-or-char` in the REPL buffer

## Expected behavior
Pressing `C-s C-w` in the REPL buffer should work as in normal buffers, i.e. incrementally select the text at point to be part of the search string.

## Actual behavior
To give you an example, let's say I run a test and it comes back with:

"FAIL in (animation-behaviour-test) (/mnt/main/dev/entmorph/test/unit/entmorph/html/canvas/scene/core_test.cljc:11862:10)"

If I now move the point to the start of "animation-behaviour-test" and try to select using `C-s C-w`, normally I would be able to incrementally add each token "animation", "behaviour", "test" on each stroke of `C-w`, whereas in the REPL buffer with the above text, it selects everything to the very end of the text output of the test.

## Steps to reproduce the problem
Run a test, and then try `C-s C-w`.

UPDATE: In fact, more generally `M-f` and `M-b` (forward-word, backword-word) when called from anywhere within the output text in the REPL will jump to the very start or very end of the text block respectively.

## Environment & Version information

### CIDER version information

*Include here the version string displayed when
CIDER's REPL is launched. Here's an example:*

```
;; CIDER 2.0.0-snapshot (package: 20260708.1419), nREPL 1.7.0
;; Clojure 1.11.1, Java 21.0.8
```

### Lein / Clojure CLI version

Clojure CLI version 1.12.1.1561

### Emacs version

GNU Emacs 30.2 (build 2, x86_64-pc-linux-gnu, GTK+ Version 3.24.50,
cairo version 1.18.4)

### Operating system

Arch Linux

### JDK distribution

openjdk version "21.0.8" 2025-07-15
OpenJDK Runtime Environment (build 21.0.8+9)
OpenJDK 64-Bit Server VM (build 21.0.8+9, mixed mode, sharing)

Reproduce the issue in a CIDER REPL by running a test, placing point in its output, and trying C-s C-w, M-f, and M-b. Trace the Emacs Lisp command and REPL buffer handling involved in word navigation; done means word-wise incremental search and movement match normal buffers within output text.

Written by the indexing model from the issue text.