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]>

Cargo.lock

@@ -2588,6 +2588,7 @@ dependencies = [
  "actix-rt",
  "actix-web",
  "anyhow",
+ "base64 0.21.7",
  "chrono",
  "futures",
  "mem-chunk",
@@ -2598,6 +2599,7 @@ dependencies = [
  "mem-store",
  "regex",
  "serde_json",
+ "sqlx",
  "time",
  "tokio",
  "toml",