Fix mainInParentDirectory failing when initdb is not on PATH

[Copilot]

When running mainInParentDirectory in wrapped dev server mode, Postgres initialization commands failed if they weren't available on the system PATH outside of the direnv environment.

Changes

• Route Postgres commands through direnv: Modified IHP.IDE.Postgres to wrap initdb, postgres, createdb, psql, and pg_ctl calls with direnv exec . when wrapWithDirenv is enabled
• Fix SQL imports: Changed from shell redirection to psql -f invocation for consistency with wrapped execution
• Fix Paths_ihp_ide.getDataFileName: Enhanced path resolution in ghci/dev mode to check IHP_LIB environment variable, enabling IHPSchema.sql discovery when running from parent directory
• Add regression test: Created Test.IDE.PostgresSpec to verify wrapped command execution and IHPSchema loading

Implementation

The fix introduces a procDirenvAware helper that conditionally wraps commands:

callProcessDirenvAware :: (?context :: Context) => OsPath -> [String] -> IO ()
callProcessDirenvAware command args = do
    commandStr <- decodeUtf command
    if ?context.wrapWithDirenv
        then Process.callProcess "direnv" (["exec", ".", commandStr] <> args)
        else Process.callProcess commandStr args

Path resolution now checks IHP_LIB before falling back to relative paths:

ihpLibCandidates :: FilePath -> IO [FilePath]
ihpLibCandidates path = do
    ihpLib <- lookupEnv "IHP_LIB"
    pure case ihpLib of
        Nothing -> []
        Just ihpLibPath ->
            let ihpIdePath = takeDirectory (takeDirectory ihpLibPath)
             in [ ihpIdePath </> path
                , ihpIdePath </> "data" </> path
                ]

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