feat: detect self-reported PATH hints to fix command-not-found after …

[KeymelGaston]

Problem

Some install scripts (e.g. openfang's curl | sh installer) install a binary, append a PATH export line to the shell rc file, and print a hint like export PATH=/some/dir:$PATH instead of updating the current shell.

Since all commands in a method run inside a single generated script (see buildAndRun in installcommand.go), that rc-file change never takes effect mid-script — so the very next command fails with command not found even though installation succeeded. This is exactly what's reported in #145.

Fix

Adds a generic handler, following the same pattern already used for pip/python swapping and the PathAugment table for known deps (Bun, PHP, Homebrew, etc.):

if !pathHintApplied && strings.Contains(strings.ToLower(output), "command not found") {
    pathHintRegex := regexp.MustCompile(`export PATH=([^\s:"']+)`)
    if matches := pathHintRegex.FindStringSubmatch(output); len(matches) > 1 {
        hintedDir := matches[1]
        // ... prepend hintedDir to the process PATH and retry
    }
}

Instead of hardcoding a per-repo special case, this parses the PATH hint the install script already prints, and applies it to the process PATH before retrying — so it generalizes to any install script that follows this common convention, not just openfang.

Testing

Reproduced the exact scenario from #145 (installing RightNow-AI/openfang on Ubuntu 24.04 / Linux Mint) with a locally built binary.

Before the fix — fails right after a successful install:

openfang Added to PATH via /home/user/.bashrc
...
/tmp/ipm-xxxxx.sh: line 4: openfang: command not found

After the fix — the hint is detected, PATH is updated, and the install completes end-to-end (init + daemon start both succeed):

/tmp/ipm-xxxxx.sh: line 4: openfang: command not found
ℹ Detected a PATH hint in the output (/home/user/.openfang/bin). Retrying with updated PATH...
...
✔ OpenFang initialized (quick mode)
...
OpenFang API server listening on http://127.0.0.1:4200

Note on scope

This ended up being more of a generalization than a narrow fix — instead of special-casing openfang, it extends the existing handler pattern to any install script that self-reports a PATH hint. Happy to narrow the approach if you'd prefer something more scoped — open to feedback before/after merge.