simplex-chat-python: add python library (#6954)

* docs: simplex-chat-python design and implementation plan

* bots: Python wire types codegen

* simplex-chat-python: package scaffold

* simplex-chat-python: native libsimplex loader

* simplex-chat-python: async FFI wrappers

* simplex-chat-python: ChatApi with 49 api methods

* simplex-chat-python: Bot class with decorators and dispatch

* simplex-chat-python: install CLI, example bot, README

* simplex-chat-python: audit fixes

* bots: regenerate API docs and types

Catches up the markdown, TypeScript and Python codegen outputs with two
upstream schema changes:

- APIConnectPlan.connectionLink became optional (from sh/python-lib audit
  fixes); cmdString and EBNF syntax now reflect optional parameter.
- APIAddGroupRelays command and CRGroupRelaysAdded/CRGroupRelaysAddFailed
  responses added in #6917 (relay management). The TS and markdown outputs
  were regenerated when #6917 landed but the Python types module only got
  the new entries with this regeneration.

* core: refresh SQLite query plans after relay_inactive_at migration

The M20260507_relay_inactive_at migration (#6917 / #6952) shifted the
query plans that 'Save query plans' verifies. Regenerated via the test
that owns those snapshots; no behavioral change.

* bots: keep APIConnectPlan connectionLink as required parameter

The prior audit-fixes commit changed the syntax expression to `Optional ...`
because the Haskell field is `connectionLink :: Maybe AConnectionLink`.
That misrepresents the API contract: the `Maybe` is purely an internal
signal for link-parsing failure (the handler returns `CEInvalidConnReq`
on `Nothing`), not API-level optionality. Callers MUST always pass a
connection link.

Revert the syntax expression to `Param "connectionLink"` and add a
comment so the intent is preserved next time someone audits.

Regenerates COMMANDS.md, commands.ts and _commands.py to match.

packages/simplex-chat-python/src/simplex_chat/__init__.py

@@ -0,0 +1,59 @@
+"""SimpleX Chat — Python client library for chat bots."""
+
+from ._version import __version__
+from .api import ChatApi, ChatCommandError, ConnReqType, Db, PostgresDb, SqliteDb
+from .bot import (
+    Bot,
+    BotCommand,
+    BotProfile,
+    ChatMessage,
+    CommandHandler,
+    EventHandler,
+    FileMessage,
+    ImageMessage,
+    LinkMessage,
+    Message,
+    MessageHandler,
+    Middleware,
+    ParsedCommand,
+    ReportMessage,
+    TextMessage,
+    UnknownMessage,
+    VideoMessage,
+    VoiceMessage,
+)
+from .core import ChatAPIError, ChatInitError, CryptoArgs, MigrationConfirmation
+from . import util as util  # re-export the util namespace
+
+__all__ = [
+    "__version__",
+    "Bot",
+    "BotCommand",
+    "BotProfile",
+    "ChatAPIError",
+    "ChatApi",
+    "ChatCommandError",
+    "ChatInitError",
+    "ChatMessage",
+    "CommandHandler",
+    "ConnReqType",
+    "CryptoArgs",
+    "Db",
+    "EventHandler",
+    "FileMessage",
+    "ImageMessage",
+    "LinkMessage",
+    "Message",
+    "MessageHandler",
+    "Middleware",
+    "MigrationConfirmation",
+    "ParsedCommand",
+    "PostgresDb",
+    "ReportMessage",
+    "SqliteDb",
+    "TextMessage",
+    "UnknownMessage",
+    "VideoMessage",
+    "VoiceMessage",
+    "util",
+]