Update algorithm and API documentation for smoking tracking app

- Enhanced the algorithm documentation to clarify the calculation of smoking intervals, including default values and edge cases.
- Updated API documentation to reflect changes in response formats, including the addition of `exceeded_yesterday` and adjustments to time formatting to RFC3339.
- Improved descriptions of user profile management and AI suggestions in the product documentation, ensuring consistency across all related files.
- Removed outdated sequence diagram and UI documentation files to streamline project resources.

docs/smoke/API.md

@@ -360,6 +360,7 @@ curl -X GET 'http://127.0.0.1:8080/api/v1/smoke/logs/5202' \
 默认策略（不使用 AI）：
 - 基础间隔：优先使用 `GET /api/v1/smoke/profile` 返回的 `baseline_interval_minutes`；若不存在则默认 `60` 分钟。
 - 阶梯式延时：最近 7 天内每累计 `5` 条“忍住记录（level=0,num=0）”，在基础间隔上 `+5` 分钟（最多 `+60` 分钟）。
+- 间隔兜底：最终间隔会限制在 `5~240` 分钟之间。
 - 若用户已补全作息时间，会自动规避睡眠区间：若计算出的时间落在睡眠区间，顺延到下一次起床时间。
 
 AI 生成说明：
@@ -373,22 +374,23 @@ AI 生成说明：
   "message": "success",
   "data": {
     "source": "default",
-    "not_before_at": "2026-01-05 10:18:00",
-    "suggested_at": "2026-01-05 10:18:00",
-    "last_smoke_at": "2026-01-05 09:30:00",
+    "not_before_at": "2026-01-05T10:18:00+08:00",
+    "suggested_at": "2026-01-05T10:18:00+08:00",
+    "last_smoke_at": "2026-01-05T09:30:00+08:00",
     "today_count": 3,
     "resisted_count": 1,
     "reduced_from_yesterday": 2,
+    "exceeded_yesterday": false,
     "default": {
-      "last_smoke_at": "2026-01-05 09:30:00",
-      "next_smoke_at": "2026-01-05 10:18:00",
+      "last_smoke_at": "2026-01-05T09:30:00+08:00",
+      "next_smoke_at": "2026-01-05T10:18:00+08:00",
       "base_interval_minutes": 48,
       "interval_minutes": 48,
       "stage": 0,
       "resisted_7d": 3,
       "sleep_adjusted": false,
       "algorithm": "staircase_delay_v1",
-      "as_of": "2026-01-05 10:00:00"
+      "as_of": "2026-01-05T10:00:00+08:00"
     }
   }
 }
@@ -401,19 +403,20 @@ AI 生成说明：
   "message": "success",
   "data": {
     "source": "ai",
-    "not_before_at": "2026-01-05 10:18:00",
-    "suggested_at": "2026-01-05 10:28:00",
-    "last_smoke_at": "2026-01-05 09:30:00",
+    "not_before_at": "2026-01-05T10:18:00+08:00",
+    "suggested_at": "2026-01-05T10:28:00+08:00",
+    "last_smoke_at": "2026-01-05T09:30:00+08:00",
     "today_count": 3,
     "resisted_count": 1,
     "reduced_from_yesterday": 2,
+    "exceeded_yesterday": false,
     "time_nodes": ["10:30", "11:10", "14:00", "16:30"],
     "advice": "先把这次冲动延后到10:28，期间做一次5分钟快走+喝水，压力场景用深呼吸替代。",
     "default": { "algorithm": "staircase_delay_v1" },
     "ai": {
       "plan_date": "2026-01-05",
-      "not_before_at": "2026-01-05 10:18:00",
-      "suggested_at": "2026-01-05 10:28:00",
+      "not_before_at": "2026-01-05T10:18:00+08:00",
+      "suggested_at": "2026-01-05T10:28:00+08:00",
       "time_nodes": ["10:30", "11:10", "14:00", "16:30"],
       "advice": "先把这次冲动延后到10:28，期间做一次5分钟快走+喝水，压力场景用深呼吸替代。",
       "prompt_version": "v1",
@@ -425,7 +428,8 @@ AI 生成说明：
 ```
 
 字段说明（新增首页字段）：
-- `last_smoke_at`：上次“实际抽烟”时间（忽略忍住记录），格式 `YYYY-MM-DD HH:MM:SS`。
+- `last_smoke_at`：上次“实际抽烟”时间（忽略忍住记录），格式 `RFC3339`（含时区）。
 - `today_count`：今日抽烟支数（累加 `num`）。
 - `resisted_count`：今日克制次数（`level=0 && num=0`）。
-- `reduced_from_yesterday`：较昨日减少的支数（`max(昨日支数 - 今日支数, 0)`）。
+- `reduced_from_yesterday`：较昨日减少的支数（允许为负数；为负时表示“今天超出昨日”）。
+- `exceeded_yesterday`：是否超出昨日（`true` 表示今天超出昨日，前端可用作单独标识）。