bar: $nalej invents cocktails, $menu keeps the bar's growing lore

The most in-character capability the bot has: the persona is literally a 200kg
bartender who mixes strong drinks with intriguing names. New always-loaded cog
bar_commands:

* $nalej [motyw] asks the ACTIVE AI backend (whatever $gadaj_teraz selects) to
  invent one themed cocktail in Conjurer's voice - persona reused from
  GPT_SETTINGS[0] as a system message, instructions as the user turn, via
  handle_response request_type NONE so it never pollutes the bar's conversation
  memory. Empty motyw = a surprise; "radio"/"pod muzykę" themes the drink on the
  track currently playing (PREPPED_TRACKS["now_playing"]).
* every drink is appended to menu.json (new seeded state file, CONJURER_MENU_FILE
  overridable) with name/theme/author/timestamp/full text - emergent bar lore.
* $menu lists the invented drinks and pours one at random from the archive.

Text-only for now; a DALL-E drink image is an easy follow-up (the render path
already exists in ai_commands, OpenAI-only).

constants gains MENU_FILE (next to pamiec.json by default) + its seed; bot.py
registers bar_commands as a core cog. Verified: tests/unit/test_bar_commands.py
covers name extraction (markers/markdown/fallback) and the menu round-trip
incl. corrupt-file tolerance; unit job 32 passed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

constants.py

@@ -203,6 +203,13 @@ TRANSCRIPTS_PATH = os.getenv(
     os.path.join(os.path.dirname(LOGFILE) or ".", "transcripts") + os.sep,
 )
 
+# The bar's growing menu of AI-invented drinks (bar_commands). Lives next to the
+# conversation memory by default; seeded empty on first run.
+MENU_FILE = os.getenv(
+    "CONJURER_MENU_FILE",
+    os.path.join(os.path.dirname(MEMORY_FIVE_SIARA) or ".", "menu.json"),
+)
+
 FILE_SERVICE_ADDRESS = os.getenv("CONJURER_FILE_SERVICE", "http://192.168.1.15:5000")
 RADIO_HARBOR_ADDRESS = os.getenv("CONJURER_RADIO_HARBOR", "http://192.168.1.15:54321")
 # Betoniarka (radio-operator service colocated with Liquidsoap). Falls back to
@@ -272,6 +279,7 @@ def _ensure_runtime_layout() -> None:
     _seed_file(SETTINGS_FILE, "settings.json", "{}")
     _seed_file(SYSTEM_GPT_SETTINGS, "system_gpt_settings.json", "{}")
     _seed_file(MEMORY_FIVE_SIARA, "pamiec.json", "[]")
+    _seed_file(MENU_FILE, "menu.json", "[]")
     _seed_file(MEMORY_FIVE_MUZYKA, "pamiec_muzyki.json", "[]")
     _seed_file(ACCIDENT_LOG, "accident_log.json", "[]")