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_inference_engine_5_2.rs

@@ -126,11 +126,11 @@ mod tests {
     /// Test: Reasoning path confidence
     #[test]
     fn test_reasoning_path_confidence() {
-        let conf1 = 0.9;
+        let conf1: f64 = 0.9;
         let conf2 = 0.9;
         let total = conf1 * conf2;
         
-        assert!((total - 0.81).abs() < 0.01);
+        assert!((total - 0.81_f64).abs() < 0.01);
     }
 
     /// Test: Max hops validation
@@ -172,17 +172,17 @@ mod tests {
     /// Test: Confidence chaining (product)
     #[test]
     fn test_confidence_chaining_product() {
-        let c1 = 0.9;
+        let c1: f64 = 0.9;
         let c2 = 0.85;
         let result = c1 * c2;
         
-        assert!((result - 0.765).abs() < 0.01);
+        assert!((result - 0.765_f64).abs() < 0.01);
     }
 
     /// Test: Confidence bounded to 1.0
     #[test]
     fn test_confidence_bounded() {
-        let conf = 1.2;
+        let conf: f64 = 1.2;
         let bounded = conf.min(1.0);
         
         assert_eq!(bounded, 1.0);