Split adapter.py monolith into focused modules; restore Ruff complexity defaults (issue #12)

adapter.py was a 3,493-line monolith. Split it into focused modules with
clear separation of responsibilities, bringing it down to ~857 lines:

- Module-level helpers: hooks, classify, pickers, commands, setup,
  defaults, secrets
- Frame-handler mixins: inbound, tool_frames, push_frames, media_frames,
  picker_frames, channel_frames, query_frames
- mixin_base: IrisAdapterBase (declaration-only base for shared attrs)
- adapter.py now holds only IrisAdapter (the composition of the 7 mixins
  + BasePlatformAdapter), register(), and test-facing re-exports

The mixins come before BasePlatformAdapter in the MRO so their methods
override the base; super() calls (e.g. send_image) still resolve to
BasePlatformAdapter. No circular imports; dispatch.py and http_server.py
(instance-method callers) are unaffected.

Ruff complexity ceilings (PLR0911/0912/0913/0915) restored to Ruff's
built-in defaults (12/50/6/5) instead of "just above the current maxima",
which ratchets the bar down as code grows. The existing genuinely-complex
functions (frame builders mirroring the wire schema, the QR matrix builder,
the dispatch table) carry an explicit `# noqa: PLR09xx` marking them as
reviewed, frozen exceptions; new code is held to the default ceilings.

All 125 tests green (94 test_android + 31 test_android_http); no new ruff
errors introduced.

gateway-plugin/pickers.py

@@ -0,0 +1,83 @@
+"""Choice-picker callbacks: clarify + exec approval.
+
+Build the ``on_choice_selected`` closures the adapter stores in
+``_pending_pickers``; a ``picker.select`` from the app runs the closure and
+delivers its reply text as a normal message.
+"""
+
+def _clarify_is_multi(clarify_id: str) -> bool:
+    """True when the pending clarify [clarify_id] allows multiple selections.
+
+    The flag lives on the gateway's pending entry; a missing/expired entry (or
+    any lookup error) is treated as single-select.
+    """
+    try:
+        from tools import clarify_gateway as _cg
+
+        with _cg._lock:
+            _entry = _cg._entries.get(clarify_id)
+        return bool(_entry and getattr(_entry, "multi_select", False))
+    except Exception:
+        return False
+
+
+def _clarify_picker_callback(clarify_id: str, choices: list[str]):
+    """Build the ``on_choice_selected`` callback for a clarify picker.
+
+    Option values are positional (``c0``..``cN``) plus an ``other`` sentinel;
+    the closure maps them back to the real choice strings. A real pick resolves
+    the clarify (the agent then continues and replies); "Other" flips the entry
+    to text-capture so the next typed message is the answer. An unmappable value
+    also flips to text so a clarify never dead-ends.
+    """
+
+    async def on_choice_selected(chat_id: str, value: str) -> str | None:
+        from tools.clarify_gateway import mark_awaiting_text, resolve_gateway_clarify
+
+        if value == "other":
+            mark_awaiting_text(clarify_id)
+            return "✏️ Type your answer:"
+        try:
+            idx = int(value[1:]) if value.startswith("c") else -1
+        except ValueError:
+            idx = -1
+        if 0 <= idx < len(choices):
+            resolve_gateway_clarify(clarify_id, choices[idx])
+            return None
+        mark_awaiting_text(clarify_id)
+        return "✏️ Type your answer:"
+
+    return on_choice_selected
+
+
+# The four exec-approval outcomes hermes understands (tools.approval).
+_APPROVAL_CHOICES = ("once", "session", "always", "deny")
+
+
+def _approval_picker_callback(session_key: str):
+    """Build the ``on_choice_selected`` callback for an exec-approval picker.
+
+    The option values are the raw hermes approval outcomes (``once`` /
+    ``session`` / ``always`` / ``deny``); a tap resolves the waiting agent
+    thread via ``resolve_gateway_approval`` (the same primitive the text
+    ``/approve`` / ``/deny`` handlers use) and returns a short confirmation
+    label, which the picker handler delivers as a normal message. An unknown
+    value is treated as a deny so a stray tap never approves a command.
+    """
+
+    async def on_choice_selected(chat_id: str, value: str) -> str | None:
+        from tools.approval import resolve_gateway_approval
+
+        choice = value if value in _APPROVAL_CHOICES else "deny"
+        count = resolve_gateway_approval(session_key, choice)
+        label = {
+            "once": "✅ Approved once",
+            "session": "✅ Approved for this session",
+            "always": "✅ Approved permanently",
+            "deny": "❌ Denied",
+        }[choice]
+        if not count:
+            label = "⌛ Approval expired — no command was waiting."
+        return label
+
+    return on_choice_selected