Remove dead CompanyFacts earnings code and eliminate all compiler warnings

Remove ~400 lines of unused code from facts.rs that was left behind after
migrating to the filing-native XBRL approach for the /em command.

- Remove dead earnings functions (build_earnings_periods, etc.)
- Remove unused utility functions (month_abbreviation, duration_value_for_period, etc.)
- Remove unused concept constants (BASIC_EPS_CONCEPTS, COST_OF_SALES_CONCEPTS, etc.)
- Simplify OverlayPeriodKind enum to only keep Any variant
- Fix unused variable warnings in dei.rs and types.rs
- Update test mocks to remove obsolete fields

Result: 0 compiler warnings (down from 35)

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

MosaicIQ/src-tauri/src/terminal/command_service.rs

@@ -1228,7 +1228,6 @@ mod tests {
                     latest_filing: None,
                     source_status: SourceStatus {
                         companyfacts_used: true,
-                        latest_xbrl_parsed: false,
                         degraded_reason: None,
                     },
                 })
@@ -1253,7 +1252,6 @@ mod tests {
                     latest_filing: None,
                     source_status: SourceStatus {
                         companyfacts_used: true,
-                        latest_xbrl_parsed: false,
                         degraded_reason: None,
                     },
                 })

MosaicIQ/src-tauri/src/terminal/sec_edgar/earnings/dei.rs

@@ -17,7 +17,7 @@ fn extract_fiscal_year_from_period_end(period_end: &str) -> Option<i32> {
 
 /// Helper to infer fiscal period from filing form and period dates
 fn infer_fiscal_period_from_duration(
-    period_start: &str,
+    _period_start: &str,
     period_end: &str,
     frequency: Frequency,
 ) -> Option<String> {

MosaicIQ/src-tauri/src/terminal/sec_edgar/types.rs

@@ -216,8 +216,10 @@ pub(crate) struct LatestXbrlFact {
     pub value: f64,
     #[allow(dead_code)]
     pub context_ref: String,
+    #[allow(dead_code)]
     pub period_start: Option<String>,
     pub period_end: Option<String>,
+    #[allow(dead_code)]
     pub is_instant: bool,
     pub has_dimensions: bool,
 }