fix: align lineloss default periods with page semantics

Default month/week deterministic lineloss requests to the source page's built-in time ranges while preserving explicit-period parsing and existing routing contracts.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/compat/tq_lineloss/period_resolver.rs

@@ -1,4 +1,4 @@
-use chrono::{Datelike, Duration, NaiveDate};
+use chrono::{Datelike, Duration, Local, NaiveDate};
 use serde_json::json;
 
 use super::contracts::{
@@ -37,7 +37,11 @@ fn resolve_month_period(input: &str) -> Result<ResolvedPeriod, String> {
         });
     }
 
-    Err(missing_period_prompt())
+    if contains_explicit_month_period_hint(input) {
+        return Err(missing_period_prompt());
+    }
+
+    Ok(default_month_period())
 }
 
 fn resolve_week_period(input: &str) -> Result<ResolvedPeriod, String> {
@@ -45,26 +49,83 @@ fn resolve_week_period(input: &str) -> Result<ResolvedPeriod, String> {
         return Err(missing_week_year_prompt());
     }
 
-    let Some((year, week)) = extract_year_week(input) else {
-        return Err(missing_period_prompt());
-    };
+    if let Some((year, week)) = extract_year_week(input) {
+        let Some(week_start) = week_start_date(year, week) else {
+            return Err(missing_period_prompt());
+        };
+        let week_end = week_start + Duration::days(6);
 
-    let Some(week_start) = week_start_date(year, week) else {
-        return Err(missing_period_prompt());
-    };
-    let week_end = week_start + Duration::days(6);
+        return Ok(ResolvedPeriod {
+            mode: PeriodMode::Week,
+            mode_code: "2".to_string(),
+            value: format!("{year}-W{week:02}"),
+            payload: json!({
+                "tjzq": "week",
+                "level": "00",
+                "weekSfdate": week_start.format("%Y-%m-%d").to_string(),
+                "weekEfdate": week_end.format("%Y-%m-%d").to_string(),
+            }),
+        });
+    }
 
-    Ok(ResolvedPeriod {
+    if contains_explicit_week_period_hint(input) {
+        return Err(missing_period_prompt());
+    }
+
+    Ok(default_week_period())
+}
+
+fn default_month_period() -> ResolvedPeriod {
+    let today = Local::now().date_naive();
+    let (year, month) = if today.month() == 1 {
+        (today.year() - 1, 12)
+    } else {
+        (today.year(), today.month() - 1)
+    };
+    let value = format!("{year}-{month:02}");
+
+    ResolvedPeriod {
+        mode: PeriodMode::Month,
+        mode_code: "1".to_string(),
+        value: value.clone(),
+        payload: json!({ "fdate": value }),
+    }
+}
+
+fn default_week_period() -> ResolvedPeriod {
+    let today = Local::now().date_naive();
+    let month_start = today.with_day(1).expect("current month should have day 1");
+    let start = month_start.format("%Y-%m-%d").to_string();
+    let end = today.format("%Y-%m-%d").to_string();
+
+    ResolvedPeriod {
         mode: PeriodMode::Week,
         mode_code: "2".to_string(),
-        value: format!("{year}-W{week:02}"),
+        value: format!("{start}至{end}"),
         payload: json!({
             "tjzq": "week",
             "level": "00",
-            "weekSfdate": week_start.format("%Y-%m-%d").to_string(),
-            "weekEfdate": week_end.format("%Y-%m-%d").to_string(),
+            "weekSfdate": start,
+            "weekEfdate": end,
         }),
-    })
+    }
+}
+
+fn contains_explicit_month_period_hint(input: &str) -> bool {
+    let trimmed = input.replace("月累计", "");
+    trimmed.contains('年')
+        || trimmed.contains('月')
+        || trimmed.contains('-')
+        || trimmed.chars().any(|ch| ch.is_ascii_digit())
+}
+
+fn contains_explicit_week_period_hint(input: &str) -> bool {
+    let trimmed = input.replace("周累计", "");
+    trimmed.contains('年')
+        || trimmed.contains('第')
+        || trimmed.contains('周')
+        || trimmed.contains('-')
+        || trimmed.chars().any(|ch| ch.is_ascii_digit())
 }
 
 fn extract_year_month_dash(input: &str) -> Option<String> {