Phase 1 foundation: Tauri shell, Python sidecar, SQLite database

Tauri v2 + Svelte + TypeScript frontend:
- App shell with workspace layout (waveform, transcript, speakers, AI chat)
- Placeholder components for all major UI areas
- Typed stores (project, transcript, playback, AI)
- TypeScript interfaces matching the database schema
- Tauri bridge service with typed invoke wrappers
- svelte-check passes with 0 errors

Rust backend:
- Tauri v2 app entry point with command registration
- SQLite database layer (rusqlite with bundled SQLite)
  - Full schema: projects, media_files, speakers, segments, words,
    ai_outputs, annotations (with indexes)
  - Model structs with serde serialization
  - CRUD queries for projects, speakers, segments, words
  - Segment text editing preserves original text
  - Schema versioning for future migrations
  - 6 tests passing
- Command stubs for project, transcribe, export, AI, settings, system
- App state management

Python sidecar:
- JSON-line IPC protocol (stdin/stdout)
- Message types: IPCMessage, progress, error, ready
- Handler registry with routing and error handling
- Ping/pong handler for connectivity testing
- Service stubs: transcribe, diarize, pipeline, AI, export
- Provider stubs: local (llama-server), OpenAI, Anthropic, LiteLLM
- Hardware detection stubs
- 14 tests passing, ruff clean

Also adds:
- Testing strategy document (docs/TESTING.md)
- Validation script (scripts/validate.sh)
- Updated .gitignore for Svelte, Rust, Python artifacts

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

python/voice_to_notes/ipc/protocol.py

@@ -0,0 +1,47 @@
+"""JSON-line protocol reader/writer over stdin/stdout."""
+
+from __future__ import annotations
+
+import json
+import sys
+from typing import Any
+
+from voice_to_notes.ipc.messages import IPCMessage
+
+
+def read_message() -> IPCMessage | None:
+    """Read a single JSON-line message from stdin. Returns None on EOF."""
+    try:
+        line = sys.stdin.readline()
+        if not line:
+            return None  # EOF
+        line = line.strip()
+        if not line:
+            return None
+        data = json.loads(line)
+        return IPCMessage.from_dict(data)
+    except json.JSONDecodeError as e:
+        _log(f"Invalid JSON: {e}")
+        return None
+    except Exception as e:
+        _log(f"Read error: {e}")
+        return None
+
+
+def write_message(msg: IPCMessage) -> None:
+    """Write a JSON-line message to stdout."""
+    line = json.dumps(msg.to_dict(), separators=(",", ":"))
+    sys.stdout.write(line + "\n")
+    sys.stdout.flush()
+
+
+def write_dict(data: dict[str, Any]) -> None:
+    """Write a raw dict as a JSON-line message to stdout."""
+    line = json.dumps(data, separators=(",", ":"))
+    sys.stdout.write(line + "\n")
+    sys.stdout.flush()
+
+
+def _log(message: str) -> None:
+    """Log to stderr (stdout is reserved for IPC)."""
+    print(f"[sidecar] {message}", file=sys.stderr, flush=True)