Pipeline Git.hs: typed git operations

Create Omni/Pipeline/Git.hs - typed git operations wrapper.

Thin wrapper around git process calls. Each function calls git via System.Process.readProcessWithExitCode and returns Either GitError a.

data GitError = GitError { geCommand :: Text, geExitCode :: Int, geStderr :: Text }

Functions:

• createWorktree :: FilePath -> Text -> Text -> IO (Either GitError FilePath)

-- (repoRoot, path, branch)

• removeWorktree :: FilePath -> FilePath -> IO (Either GitError ())
• checkoutBranch :: FilePath -> Text -> IO (Either GitError ())
• createBranch :: FilePath -> Text -> Text -> IO (Either GitError ())

-- (workspace, branchName, startPoint)

• deleteBranch :: FilePath -> Text -> IO (Either GitError ())
• cherryPick :: FilePath -> Text -> IO (Either GitError Text)

-- returns commit hash on success

• abortCherryPick :: FilePath -> IO (Either GitError ())
• commitCountBetween :: FilePath -> Text -> Text -> IO (Either GitError Int)
• currentBranchSha :: FilePath -> Text -> IO (Maybe Text)
• isCleanWorkspace :: FilePath -> IO Bool
• worktreeExists :: FilePath -> IO Bool
• revertLastCommit :: FilePath -> IO (Either GitError ())

Include a helper: runGit :: FilePath -> [String] -> IO (Either GitError String)

No tests needed for this module - it's a thin wrapper. Verified by typecheck.

Verify: typecheck.sh Omni/Pipeline/Git.hs