fix: Python startup no longer silent on first run

ROOT CAUSE

User reported the Python edition showed "только пустой терминал" — empty
terminal — when launched. Three compounding issues:

1. `tts.py` called `torch.hub.load(...)` at MODULE IMPORT time. On first
   use this downloads a 60MB Silero model with no progress output beyond
   one "Using cache found in..." line. With no prior banner the user
   couldn't tell if it crashed or was loading.
2. main.py's startup banner (`print("=" * 60)...J.A.R.V.I.S. v...`)
   appeared AFTER all the heavy imports. So even when nothing was wrong,
   visible feedback was delayed by 10-60 seconds.
3. If `pip install -r requirements.txt` failed for any package
   (`simpleaudio` notoriously needs MSVC to build), `import simpleaudio`
   crashed the whole process with a raw ModuleNotFoundError.

FIXES

- `tts.py`: Silero model load moved into `_ensure_model()` called lazily
  from `synthesize()`. First synth pays the load cost (with a one-line
  progress hint) — everything before that is visible immediately.
- `main.py`: print "J.A.R.V.I.S. loading..." banner BEFORE any heavy
  imports. User sees the terminal is alive within ~100ms.
- `main.py`: scan required deps before importing them; if any are
  missing, print "Run: pip install -r requirements.txt" with the
  specific list and exit cleanly (exit code 2) instead of stack-tracing.
- `main.py`: `simpleaudio` is now soft-optional. Falls back to stdlib
  `winsound` on Windows installs that couldn't build the C extension.
  Sound cues still work; only the precise wait_done semantics are
  slightly different.

VERIFIED LOCALLY

`.venv\Scripts\python.exe main.py` now prints:
```
============================================================
  J.A.R.V.I.S.  loading (Python edition)...
  Heavy modules (vosk / torch / pvrecorder) take a few seconds.
============================================================
[scheduler] thread started (1 tasks loaded)
============================================================
  J.A.R.V.I.S.  v0.4.1   [Python edition]
  Total commands: 200
============================================================
Using device: Микрофон (5- Fifine Microphone)
Jarvis (v0.4.1) начал свою работу ...
Yes, sir.
```

Total time to first banner: ~100ms (was 10-60s of nothing).
All 104 pytest tests still pass.

main.py

@@ -10,14 +10,66 @@ import time
 import webbrowser
 from ctypes import POINTER, cast
 
+# Print a startup banner BEFORE the heavy imports — otherwise the user
+# sees an empty terminal for 10-60 seconds while torch / vosk / silero
+# load. This used to be the #1 "did it crash?" support issue.
+print("=" * 60, flush=True)
+print("  J.A.R.V.I.S.  loading (Python edition)...", flush=True)
+print("  Heavy modules (vosk / torch / pvrecorder) take a few seconds.", flush=True)
+print("=" * 60, flush=True)
+
+# Helpful diagnostic: if a critical dep is missing, tell the user EXACTLY
+# what to install instead of dumping a raw ModuleNotFoundError. Pulls
+# every required package by name and reports them in one go.
+_MISSING_DEPS = []
+for _modname, _pkg in [
+    ("numpy", "numpy"),
+    ("openai", "openai>=1.0"),
+    ("vosk", "vosk"),
+    ("webrtcvad", "webrtcvad"),
+    ("yaml", "PyYAML"),
+    ("comtypes", "comtypes"),
+    ("fuzzywuzzy", "fuzzywuzzy"),
+    ("pvrecorder", "pvrecorder"),
+    ("pycaw", "pycaw"),
+    ("rich", "rich"),
+]:
+    try:
+        __import__(_modname)
+    except ImportError:
+        _MISSING_DEPS.append(_pkg)
+if _MISSING_DEPS:
+    print("\n[ERROR] Missing Python packages:", flush=True)
+    for _p in _MISSING_DEPS:
+        print(f"  - {_p}", flush=True)
+    print("\nRun:  pip install -r requirements.txt", flush=True)
+    print("Or use the bundled venv: launch via run.bat.\n", flush=True)
+    sys.exit(2)
+
 import numpy as np
 import openai
 from openai import OpenAI
-import simpleaudio as sa
 import vosk
 import webrtcvad
 import yaml
 
+# simpleaudio needs MSVC to build from source; gracefully fall back to the
+# stdlib's `winsound` on Windows when it isn't installed.
+try:
+    import simpleaudio as sa
+    _HAS_SIMPLEAUDIO = True
+except ImportError:
+    sa = None
+    _HAS_SIMPLEAUDIO = False
+    try:
+        import winsound as _winsound
+    except ImportError:
+        _winsound = None
+    if _winsound is None:
+        print("[WARN] Neither simpleaudio nor winsound available — sound cues disabled.", flush=True)
+    else:
+        print("[INFO] simpleaudio not installed; falling back to winsound for sound cues.", flush=True)
+
 import extensions  # new-command handlers ported from rust fork
 import plugins_store  # user plugin packs under APP_CONFIG_DIR/plugins/
 from comtypes import CLSCTX_ALL
@@ -154,14 +206,24 @@ def play(phrase, wait_done=True):
     if wait_done:
         recorder.stop()
 
-    wave_obj = sa.WaveObject.from_wave_file(filename)
-    play_obj = wave_obj.play()
+    # Prefer simpleaudio (lets us wait_done precisely); fall back to winsound
+    # on installs that couldn't build the simpleaudio C extension.
+    if _HAS_SIMPLEAUDIO and sa is not None:
+        wave_obj = sa.WaveObject.from_wave_file(filename)
+        play_obj = wave_obj.play()
+        if wait_done:
+            play_obj.wait_done()
+    elif _winsound is not None:
+        flags = _winsound.SND_FILENAME
+        if not wait_done:
+            flags |= _winsound.SND_ASYNC
+        try:
+            _winsound.PlaySound(filename, flags)
+        except RuntimeError as exc:
+            print(f"[sound] winsound playback failed: {exc}")
+    # else: no audio backend — silently skip cue
 
     if wait_done:
-        play_obj.wait_done()
-        # time.sleep((len(wave_obj.audio_data) / wave_obj.sample_rate) + 0.5)
-        # print("END")
-        # time.sleep(0.5)
         recorder.start()