feat(parsing): opt-out of shell-style backslash escaping (EscapeLiteral)

[maxlandon]

Closes #88.

Problem

The console splits every input line with POSIX shell semantics, so an unquoted backslash escapes the next character. When the console is used as a general Cobra frontend rather than a shell, this is surprising:

• ls C:\Windows\Temp reaches the command as ["ls", "C:WindowsTemp"] — the backslashes are eaten.
• ls C:\Windows\Temp\ is treated as an incomplete line (trailing backslash = continuation) and blocks waiting for more input.

Users currently have to quote the whole value ('C:\Windows\Temp') or double every backslash. As @h3zh1 noted in #88, that's cumbersome for a Cobra-frontend use case.

I confirmed empirically that the mvdan.cc/sh comment-stripping stage is innocent — it round-trips backslashes untouched. The mangling comes entirely from the shellquote-derived word splitters.

Solution

A console-wide EscapeMode, default unchanged:

app := console.New("myapp")
app.SetEscapeMode(console.EscapeLiteral)

Mode	Behavior
EscapeShell (default)	POSIX escape rules — byte-for-byte unchanged
EscapeLiteral	backslash is an ordinary char; quotes still group words; C:\Windows\Temp passes through verbatim; a trailing backslash no longer requests another line

Implementation: each of the three shellquote-derived splitters gained an EscapeMode parameter; in literal mode the case char == EscapeChar branch is simply skipped, so backslash falls through as a plain rune. Because literal mode never enters the escape state, ErrUnterminatedEscape can't fire — the trailing-backslash multiline bug is fixed for free, while unterminated quotes still correctly request more input.

Per the design discussion, the mode is threaded through all three call sites — command execution (line.Parse), multiline detection (AcceptMultiline), and completion/highlighting — so a C:\ path also completes and highlights consistently. Menu.RunCommandLine honors it too.

Tests

• All pre-existing EscapeShell tests pass unmodified (only the new mode arg threaded through).
• New literal-mode unit tests in internal/line and internal/completion.
• New end-to-end TestRunCommandLineEscapeMode proving the mode reaches the actual arg vector a cobra command receives — including a case pinning the current shell-mode C:\Windows\Temp → C:WindowsTemp behavior for contrast.

go build, go vet, go test ./... all green.

🤖 Generated with Claude Code

[codecov]

Codecov Report

❌ Patch coverage is 80.00000% with 9 lines in your changes missing coverage. Please review.
✅ Project coverage is 27.32%. Comparing base (f44dc1d) to head (397edc2).

Files with missing lines	Patch %	Lines
internal/completion/line.go	75.00%	2 Missing and 1 partial ⚠️
console.go	80.00%	1 Missing and 1 partial ⚠️
internal/line/line.go	84.61%	0 Missing and 2 partials ⚠️
run.go	75.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #89      +/-   ##
==========================================
+ Coverage   26.75%   27.32%   +0.57%     
==========================================
  Files          28       28              
  Lines        2119     2137      +18     
==========================================
+ Hits          567      584      +17     
+ Misses       1505     1503       -2     
- Partials       47       50       +3     

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