fix: resolve 8 integration test compilation errors (#46)

## Problem
8 integration test files failed to compile due to:
1. Ambiguous float types (Rust 2024+ stricter inference)
2. chrono 0.4 API change (`with_hour` removed)
3. Missing `sqlx` + `base64` in `[dev-dependencies]`
4. `<` parsed as generics instead of comparison
5. Incorrect assertion (3^5=243 > 100)

## Fix
- Added `f32`/`f64` type annotations to vec declarations and bindings
- Replaced `with_hour(0)` with `date_naive().and_hms_opt(0,0,0).unwrap().and_utc()`
- Added `sqlx` + `base64` to `[dev-dependencies]`
- Wrapped comparison in parens
- Fixed assertion: nodes=100 → nodes=1000

## Validation
- `cargo build --release` clean
- `cargo test` — 20 test suites, 0 failures
- 10 files changed, 46 insertions, 42 deletionsReviewed-on: #46

Co-authored-by: rock <[email protected]>

tests/it_semantic_retrieval_4_1.rs

@@ -67,7 +67,7 @@ mod tests {
     /// Test: Score normalization (clamped to 0.0-1.0)
     #[test]
     fn test_score_normalization() {
-        let test_scores = vec![
+        let test_scores: Vec<(f32, f32)> = vec![
             (-0.5, 0.0),   // Negative → 0.0
             (0.0, 0.0),    // Valid → 0.0
             (0.5, 0.5),    // Valid → 0.5
@@ -76,7 +76,7 @@ mod tests {
         ];
 
         for (input, expected) in test_scores {
-            let normalized = input.max(0.0).min(1.0);
+            let normalized = input.max(0.0_f32).min(1.0_f32);
             assert_eq!(normalized, expected, "Normalizing {} should give {}", input, expected);
         }
     }
@@ -84,15 +84,15 @@ mod tests {
     /// Test: RRF fusion weight validation
     #[test]
     fn test_rrf_weight_validation() {
-        let sem_weight = 0.6;
-        let lex_weight = 0.4;
+        let sem_weight: f32 = 0.6;
+        let lex_weight: f32 = 0.4;
 
         assert!(sem_weight >= 0.0 && sem_weight <= 1.0);
         assert!(lex_weight >= 0.0 && lex_weight <= 1.0);
         
         // Weights should be normalized
-        let sem_normalized = sem_weight.max(0.0).min(1.0);
-        let lex_normalized = lex_weight.max(0.0).min(1.0);
+        let sem_normalized = sem_weight.max(0.0_f32).min(1.0_f32);
+        let lex_normalized = lex_weight.max(0.0_f32).min(1.0_f32);
         
         assert_eq!(sem_normalized, 0.6);
         assert_eq!(lex_normalized, 0.4);
@@ -101,10 +101,10 @@ mod tests {
     /// Test: RRF fusion score calculation
     #[test]
     fn test_rrf_fusion_score_calculation() {
-        let semantic_score = 0.92;
-        let lexical_score = 0.85;
-        let sem_weight = 0.6;
-        let lex_weight = 0.4;
+        let semantic_score: f32 = 0.92;
+        let lexical_score: f32 = 0.85;
+        let sem_weight: f32 = 0.6;
+        let lex_weight: f32 = 0.4;
 
         let fused_score = (sem_weight * semantic_score) + (lex_weight * lexical_score);