[gauravchahal20]

Summary

Resolves piper next to sys.executable (e.g. .venv/bin or .venv/Scripts) before falling back to PATH, so PiperTTS is detected as AVAILABLE and functions when executing via virtualenv Python without an activated virtualenv environment on PATH.

Related issue

Closes #888

Root Cause

piper installs its CLI script into the virtualenv's binary directory (.venv/bin on POSIX or .venv/Scripts on Windows). When an agent, IDE, or script runs .venv/bin/python without activating the virtualenv, shutil.which("piper") checks only the inherited PATH and fails to locate piper. Consequently, preflight reports tts 0/18 and pipelines requiring local offline TTS are blocked.

Changes

• Added PiperTTS._find_piper: checks for piper or piper.exe in Path(sys.executable).parent before checking shutil.which("piper").
• Updated PiperTTS.get_status() to use self._find_piper().
• Implemented PiperTTS.check_dependencies() to verify binary presence via self._find_piper().
• Updated PiperTTS._generate() to invoke the resolved executable path.
• Added unit tests in tests/tools/test_piper_tts.py covering resolution next to sys.executable, fallback to PATH, unavailable handling, and invocation path passing.

Testing

Ran pytest tests/tools/test_piper_tts.py:

• 10 passed in 0.25s

Ran pytest tests/tools/test_piper_routing_consolidation.py:

• 6 passed in 0.15s

Checklist

• The change is focused on a single logical concern.
• I ran the relevant tests locally (make test-contracts / make test) where applicable.
• I updated docs/README if behavior or usage changed.
• No unrelated files (build artifacts, local config) are included in the diff.