feat: switch config to JSONC + split secrets.json

Load business config as JSONC (comments + trailing commas) via an
in-repo stripper then stdlib json — no new deps. Default path prefers
config.jsonc, falls back to legacy config.json. Auth write-back targets
only sibling secrets.json so JSONC comments are never wiped; secrets
overlay merges on load. Examples, compose, Docker, docs, favsort and
tools all share the same loader. Phase A only — no DB settings migration.

reaction_board/jsonc.py

@@ -0,0 +1,107 @@
+# -*- coding: utf-8 -*-
+"""JSONC（JSON with Comments）加载。
+
+选择**自研轻量剥离**而非引入第三方依赖：本仓库运行依赖目前只有 ``httpx``，
+配置加载属于启动/热更新热路径，JSONC 只需注释与尾逗号。实现按字符扫描，
+在字符串字面量内保留 ``//``、``/*``、引号转义，避免误伤。
+
+支持：
+- ``//`` 行注释、``/* ... */`` 块注释
+- 对象/数组中的尾逗号
+- UTF-8 BOM
+不支持 JSON5 扩展（无引号键、单引号、十六进制、``Infinity`` 等）。
+"""
+
+from __future__ import annotations
+
+import json
+from typing import Any
+
+
+def strip_jsonc(text: str) -> str:
+    """去掉 JSONC 注释与尾逗号，返回可交给 ``json.loads`` 的文本。"""
+    if text.startswith("\ufeff"):
+        text = text[1:]
+    out: list[str] = []
+    i = 0
+    n = len(text)
+    in_string = False
+    escape = False
+    while i < n:
+        ch = text[i]
+        if in_string:
+            out.append(ch)
+            if escape:
+                escape = False
+            elif ch == "\\":
+                escape = True
+            elif ch == '"':
+                in_string = False
+            i += 1
+            continue
+        if ch == '"':
+            in_string = True
+            out.append(ch)
+            i += 1
+            continue
+        if ch == "/" and i + 1 < n:
+            nxt = text[i + 1]
+            if nxt == "/":
+                i += 2
+                while i < n and text[i] not in "\r\n":
+                    i += 1
+                continue
+            if nxt == "*":
+                i += 2
+                while i + 1 < n and not (text[i] == "*" and text[i + 1] == "/"):
+                    i += 1
+                i = min(i + 2, n)
+                continue
+        out.append(ch)
+        i += 1
+
+    stripped = "".join(out)
+    # 去掉尾逗号：`,}` / `,]`（可夹空白）
+    cleaned: list[str] = []
+    i = 0
+    m = len(stripped)
+    in_string = False
+    escape = False
+    while i < m:
+        ch = stripped[i]
+        if in_string:
+            cleaned.append(ch)
+            if escape:
+                escape = False
+            elif ch == "\\":
+                escape = True
+            elif ch == '"':
+                in_string = False
+            i += 1
+            continue
+        if ch == '"':
+            in_string = True
+            cleaned.append(ch)
+            i += 1
+            continue
+        if ch == ",":
+            j = i + 1
+            while j < m and stripped[j] in " \t\r\n":
+                j += 1
+            if j < m and stripped[j] in "}]":
+                i += 1
+                continue
+        cleaned.append(ch)
+        i += 1
+    return "".join(cleaned)
+
+
+def loads(text: str) -> Any:
+    """解析 JSONC 文本。"""
+    return json.loads(strip_jsonc(text))
+
+
+def load(path: str | bytes, *, encoding: str = "utf-8") -> Any:
+    """从路径读取并解析 JSONC / JSON。"""
+    with open(path, encoding=encoding) as fh:
+        return loads(fh.read())