feat: Windows/PowerShell support, runtime snip check, pipe fix, deduplication

[qSebastiaNp]

Summary

Combines improvements from multiple community contributions:

• Runtime snip check (PR fix: use snip check/run subcommands, fix pipe handling, fix multi-word args for snip check #14): Replace hardcoded UNPROXYABLE_COMMANDS with runtime snip check calls. Requires snip >= 0.16.0.
• Fix pipe handling (PR fix: use snip check/run subcommands, fix pipe handling, fix multi-word args for snip check #14): Wrap ALL pipe segments individually, not just the first.
• Snip prefix deduplication (PR fix: snip prepend duplication (#15) #17): Prevent snip snip snip go test duplication.
• Windows support: Use where snip instead of which snip.
• PowerShell support (PR feat: add Windows/PowerShell support #21): Skip $env, splatting, cmdlets, call operator.
• Newline splitting (PR feat: add Windows/PowerShell support #21): Split multi-line commands.
• Heredoc safety (PR feat: add Windows/PowerShell support #21): Don't split heredoc bodies.
• Quote-aware pipe splitting.
• Error guard: Leave command unmodified if shouldWrap throws.
• System prompt injection via experimental.chat.system.transform.
• Use client.app.log instead of console.warn.

Breaking Changes

Minimum snip version is now >= 0.16.0 (snip run -- syntax).

Testing

60 tests passing.

[greptile-apps]

Greptile Summary

This PR expands the snip command wrapper across more shells and command shapes. The main changes are:

• Runtime snip check gating and snip run -- wrapping.
• Pipe, newline, heredoc, and redirection handling updates.
• Windows and PowerShell skip logic.
• Snip prefix deduplication and plugin logging through client.app.log.

Confidence Score: 4/5

This is close, but the heredoc parsing issue should be fixed before merging.

• Pipe-stderr and combined-redirection handling look addressed.
• Heredoc delimiter matching can still split valid heredoc bodies too early.
• That early split can route body text through normal command rewriting.

src/index.ts

Important Files Changed

Filename	Overview
src/index.ts	Adds the main wrapping pipeline, platform checks, pipe splitting, runtime snip checks, and heredoc handling.
src/index.test.ts	Adds coverage for wrapping, redirections, pipe handling, PowerShell skips, newline splitting, and simple heredoc bodies.

_{Reviews (3): Last reviewed commit: "fix: heredoc operator splitting and full..." | Re-trigger Greptile}

[greptile-apps]

Raw Partial Check Misclassifies Commands

shouldWrap sends only the first two whitespace-split words to snip check and interpolates them as raw shell text. Commands whose eligibility depends on later flags can be checked against the wrong input, and quoted words like echo "hello world" can make the check command syntactically invalid, causing the command to run unwrapped.

[greptile-apps]

Anchor heredoc delimiters

indexOf(delimiter, bodyStart) treats the first matching text as the heredoc terminator, even when it appears inside the body. A command such as cat <<EOF\nEOF marker\necho hi\nEOF is valid shell input, but this code splits at the EOF in EOF marker. The remaining body then goes through normal operator splitting, so body lines can be rewritten with snip run -- and change what the shell receives. Match the delimiter only when it appears as a real heredoc terminator line, including the tab-prefixed form for <<-.