refactor: root-package imports (svc/runtime/interfaces) and fix PYTHONPATH

- Rename platform/ to svc/ to avoid shadowing stdlib platform.
- Replace from oclaw.* with from svc/runtime/interfaces; update -m CLI paths.
- tests/conftest: prepend repo root to sys.path (no parent-folder package name).
- CI: paths and offline_eval script under repo root.
- Ops scripts: PYTHONPATH must be repo root for python -m runtime.* (fixes gateway/WhatsApp sidecar startup).
- Fix default oclaw.json path in tabular/file attachment limits; stabilize attachment test config.

Co-authored-by: Cursor <cursoragent@cursor.com>

platform/llm/transports/base.py

@@ -1,63 +0,0 @@
-from __future__ import annotations
-
-import base64
-import json
-from dataclasses import dataclass
-from typing import Any, Optional
-from collections.abc import Callable
-
-
-@dataclass(frozen=True)
-class LLMToolCall:
-    id: str
-    name: str
-    arguments: dict[str, Any]
-    # Gemini OpenAI-compat and native transports may require preserving a signature across tool loops.
-    thought_signature: str | None = None
-
-
-@dataclass(frozen=True)
-class LLMResponse:
-    content: str
-    tool_calls: list[LLMToolCall]
-    reasoning_content: str = ""
-
-
-class ChatModel:
-    def chat(
-        self,
-        messages: list[dict[str, Any]],
-        tools: list[dict[str, Any]],
-        *,
-        on_token: Optional[Callable[[str], None]] = None,
-    ) -> LLMResponse:
-        raise NotImplementedError
-
-
-def coerce_thought_signature_for_storage(v: Any) -> str | None:
-    if v is None:
-        return None
-    if isinstance(v, str):
-        return v
-    if isinstance(v, (bytes, bytearray)):
-        try:
-            return bytes(v).decode("utf-8")
-        except UnicodeDecodeError:
-            return base64.b64encode(bytes(v)).decode("ascii")
-    if isinstance(v, (dict, list)):
-        return json.dumps(v, separators=(",", ":"), ensure_ascii=False)
-    return str(v)
-
-
-def normalize_image_b64_payload(raw: Any) -> str:
-    if raw is None:
-        return ""
-    if isinstance(raw, (bytes, bytearray)):
-        return base64.b64encode(bytes(raw)).decode("ascii")
-    s = str(raw).strip()
-    if not s:
-        return ""
-    if s.startswith("data:") and ";base64," in s:
-        s = s.split(";base64,", 1)[-1].strip()
-    return "".join(s.split())
-