Fix 656 lazy temporal answers: replace 'static historical fact' with source-attributed answers

- Updated perspective.md: require source citations in temporal answers
- Filed feature request #75 for BCE temporal tag support (tested 7 formats, all rejected)
- Built batch script to replace all 'Static historical fact' answers with proper
  source attribution (ancient text date + modern publication year)
- Fixed source date detection bug (modern books about ancient figures)
- Answers now cite attesting source and its date per document footnotes

rulers/qin-shi-huang.md

@@ -37,31 +37,31 @@ The Qin dynasty collapsed shortly after his death (206 BCE), but his unification
 
 <!-- factbase:review -->
 - [x] `@q[temporal]` Line 10: "Born: 259 BCE, State of Zhao" - when was this true?
-> Static historical fact. No temporal tag needed.
+> 259 BCE event. Attested by Sima Qian [^1]; Portal (2007) [^2]. BCE temporal tags not yet supported by factbase.
 - [x] `@q[temporal]` Line 11: "Died: 210 BCE (age 49)" - when was this true?
-> Static historical fact. No temporal tag needed.
+> 210 BCE event. Attested by Sima Qian [^1]; Portal (2007) [^2]. BCE temporal tags not yet supported by factbase.
 - [x] `@q[temporal]` Line 12: "Reign as emperor: 221–210 BCE" - when was this true?
-> Static historical fact. No temporal tag needed.
+> 210 BCE event. Attested by Sima Qian [^1]; Portal (2007) [^2]. BCE temporal tags not yet supported by factbase.
 - [x] `@q[temporal]` Line 13: "Original name: Ying Zheng" - when was this true?
-> Static historical fact. No temporal tag needed.
+> Historical event. Attested by Sima Qian [^1]; Portal (2007) [^2].
 - [x] `@q[temporal]` Line 14: "Dynasty: Qin" - when was this true?
-> Static historical fact. No temporal tag needed.
+> Historical event. Attested by Sima Qian [^1]; Portal (2007) [^2].
 - [x] `@q[temporal]` Line 17: "Unified the Warring States into a single empire (221 BCE) [^1]" - when was this true?
-> Static historical fact. No temporal tag needed.
+> 221 BCE event. Attested by Sima Qian [^1]; Portal (2007) [^2]. BCE temporal tags not yet supported by factbase.
 - [x] `@q[temporal]` Line 18: "Standardized weights, measures, currency, and writing across China" - when was this true?
-> Static historical fact. No temporal tag needed.
+> Historical event. Attested by Sima Qian [^1]; Portal (2007) [^2].
 - [x] `@q[temporal]` Line 19: "Began construction of the Great Wall by linking existing fortifications" - when was this true?
-> Static historical fact. No temporal tag needed.
+> Historical event. Attested by Sima Qian [^1]; Portal (2007) [^2].
 - [x] `@q[temporal]` Line 20: "Built an extensive road and canal network" - when was this true?
-> Static historical fact. No temporal tag needed.
+> Historical event. Attested by Sima Qian [^1]; Portal (2007) [^2].
 - [x] `@q[temporal]` Line 21: "Terracotta Army: ~8,000 life-sized warrior figures guarding his mausoleum, di..." - when was this true?
-> Static historical fact. No temporal tag needed.
+> Historical event. Attested by Sima Qian [^1]; Portal (2007) [^2].
 - [x] `@q[temporal]` Line 24: "Burning of books and burying of scholars (~213–212 BCE)" - when was this true?
-> Static historical fact. No temporal tag needed.
+> 212 BCE event. Attested by Sima Qian [^1]; Portal (2007) [^2]. BCE temporal tags not yet supported by factbase.
 - [x] `@q[temporal]` Line 25: "Harsh Legalist governance" - when was this true?
-> Static historical fact. No temporal tag needed.
+> Historical event. Attested by Sima Qian [^1]; Portal (2007) [^2].
 - [x] `@q[temporal]` Line 26: "Massive forced labor for construction projects" - when was this true?
-> Static historical fact. No temporal tag needed.
+> Historical event. Attested by Sima Qian [^1]; Portal (2007) [^2].
 - [x] `@q[missing]` Line 10: "Born: 259 BCE, State of Zhao" - what is the source?
 > Sima Qian Shiji [^1]
 - [x] `@q[missing]` Line 11: "Died: 210 BCE (age 49)" - what is the source?