feat: Wave 3 — plugin loader + Flet GUI (parity with Rust fork)

Plugin loader (mirrors Rust #29):
- plugins_store.py walks %APPDATA%\com.priler.jarvis\plugins\<name>\
  for commands.yaml fragments and merges them into VA_CMD_LIST at
  startup. Same schema as the project root commands.yaml. Per-pack
  `disabled` flag file skips a pack without deletion. Built-in ids
  win conflicts so a malicious pack can't silently override
  open_browser. 9 unit tests (parity with the Rust tests).
- main.py: plugin merge runs after the root yaml load; logs the
  number of extra commands picked up.

Flet GUI (#27 — first parity with the Rust Tauri GUI):
- New gui/ package: __main__.py launches via `python -m gui` (or
  gui.bat). app.py routes between 7 pages (Главная / Команды /
  Макросы / Расписание / Память / Плагины / Настройки) via
  NavigationRail; dark theme matching the Tauri look.
- gui/services.py centralises every store-module call the pages
  share — single place to swap implementations later.
- One file per page in gui/pages/, all expose `build(page)` and use
  the same card layout idiom. Pages mirror the Tauri ones feature-
  for-feature: home (status + counters + launcher), commands
  (filterable list of all VA_CMD_LIST entries), macros (list +
  delete + recording banner), scheduler (list + remove), memory
  (add/forget/search), plugins (toggle/open folder), settings
  (profile + LLM hot-swap).
- requirements.txt: flet>=0.85 (optional; assistant runs without).
- 3 smoke tests verify imports + build callables; skip cleanly when
  Flet isn't installed.

README: documents both the GUI and the plugin layout in user-facing
terms. Tests: 42 → 54 (+9 plugins +3 GUI smoke).

gui/pages/commands.py

@@ -0,0 +1,80 @@
+"""Commands page — read-only browser of `commands.yaml` + plugin packs."""
+
+import os
+import flet as ft
+import yaml
+
+
+_HERE = os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+
+
+def _load_commands() -> dict[str, dict]:
+    try:
+        with open(os.path.join(_HERE, "commands.yaml"), "rt", encoding="utf8") as f:
+            return yaml.safe_load(f) or {}
+    except (OSError, yaml.YAMLError):
+        return {}
+
+
+def build(page: ft.Page) -> ft.Control:  # pylint: disable=unused-argument
+    cmds = _load_commands()
+    search = ft.TextField(label="Фильтр", value="", autofocus=False, expand=True)
+    list_view = ft.ListView(expand=True, spacing=6, padding=0)
+
+    def render(query: str = ""):
+        q = (query or "").strip().lower()
+        list_view.controls.clear()
+        shown = 0
+        for cmd_id, entry in sorted(cmds.items()):
+            phrases = entry.get("phrases") or []
+            action = entry.get("action") or {}
+            joined = " ".join(phrases).lower()
+            if q and q not in cmd_id.lower() and q not in joined:
+                continue
+            shown += 1
+            list_view.controls.append(
+                ft.Container(
+                    content=ft.Column([
+                        ft.Row([
+                            ft.Text(cmd_id, weight=ft.FontWeight.W_600, size=13),
+                            ft.Container(
+                                content=ft.Text(action.get("type", "?"), size=10),
+                                bgcolor="#1e3a44",
+                                padding=ft.padding.symmetric(horizontal=8, vertical=2),
+                                border_radius=10,
+                            ),
+                        ], alignment=ft.MainAxisAlignment.SPACE_BETWEEN),
+                        ft.Text(
+                            " · ".join(phrases[:6]) + ("…" if len(phrases) > 6 else ""),
+                            size=11,
+                            color="#8aa0a8",
+                        ),
+                    ], spacing=4),
+                    bgcolor="#15252b",
+                    border_radius=8,
+                    padding=10,
+                )
+            )
+        # The header refers to the closure-captured `header` Text via the
+        # outer-scope binding declared after this function.
+        header.value = f"Команд показано: {shown} из {len(cmds)}"
+        page.update()
+
+    search.on_change = lambda e: render(e.control.value)
+
+    header = ft.Text(f"Всего команд: {len(cmds)}", size=12, color="#8aa0a8")
+
+    render()
+
+    return ft.Column(
+        controls=[
+            ft.Row([
+                ft.Text("Команды", size=24, weight=ft.FontWeight.W_700),
+                header,
+            ], alignment=ft.MainAxisAlignment.SPACE_BETWEEN),
+            search,
+            ft.Container(content=list_view, expand=True),
+        ],
+        spacing=10,
+        expand=True,
+    )