Problem

When piping ollama run output to a file or another command, the output contains ANSI escape sequences like \x1b[14D (cursor back) and \x1b[K (clear line). These are part of the word-wrap logic and only make sense on a real terminal. In redirected output they appear as garbage:

$ ollama run llama3.2 "explain quantum computing" > output.txt
$ cat -v output.txt
Quantum computing is...\x1b[14D\x1b[K...

Reported in #16785.

Fix

Add a plainText bool parameter to displayResponse(). When true, the word-wrap path (which emits escape sequences) is skipped entirely and content is printed as plain text.

The generate() function already computes plainText := !term.IsTerminal(int(os.Stdout.Fd())) — this PR threads it through to displayResponse() so the function knows whether it's writing to a terminal or not.

Chat mode calls pass plainText=false since chat is always interactive. Generate mode uses the already-computed plainText value.

Why not PR #16840's approach?

PR #16840 checks term.GetSize() errors to detect non-TTY output. That works but has a subtle issue: term.GetSize() can fail for reasons other than "not a TTY" (e.g., the TTY exists but its size can't be determined). In those cases, word-wrap should still be disabled since we don't know the terminal width, but the approach conflates "can't get size" with "not a terminal."

This PR is more explicit:

• The intent is clear in the function signature (plainText bool)
• Call sites make the decision at the right level (the caller knows whether it's interactive or not)
• No behavior change for the interactive path — chat mode always passes false
• The generate() function already had the plainText variable ready to thread through

Test Plan

3 new sub-tests under TestDisplayResponseNoEscapesWhenPlainText:

• plain_text_no_escapes: verifies no \x1b bytes in output when plainText=true with long content that would normally wrap
• interactive_with_escapes: verifies plainText=false doesn't crash and produces output
• plain_text_short_content: verifies short content passes through unchanged when plainText=true

=== RUN   TestDisplayResponseNoEscapesWhenPlainText
=== RUN   TestDisplayResponseNoEscapesWhenPlainText/plain_text_no_escapes
=== RUN   TestDisplayResponseNoEscapesWhenPlainText/interactive_with_escapes
=== RUN   TestDisplayResponseNoEscapesWhenPlainText/plain_text_short_content
--- PASS: TestDisplayResponseNoEscapesWhenPlainText (0.00s)

Full cmd test suite passes.

Closes #16785