chore(deps): batch update 5 dependencies (#48)

* chore(deps): batch update 5 dependencies

- toml: 1.0 → 1.1 (semver-minor, no API changes)
- criterion: 0.5 → 0.8 (dev-dependency, benchmarks only)
- notify: 7 → 8 (macOS-irrelevant breaking changes, API stable)
- portable-pty: 0.8 → 0.9 (internal cleanup, no consumer API changes)
- yaml: 2.8.2 → 2.8.3 (fixes CVE-2026-33532, fig-converter transitive dep)

All 525 tests pass. Clippy clean. No source code changes.
Supersedes Dependabot PRs #19, #37, #39, #45, #46.

* chore: bump MSRV from 1.75 to 1.86

toml 1.1 and criterion 0.8 declare MSRV 1.85+. The previous 1.75
claim only held because older Cargo doesn't enforce dep MSRVs —
not a real guarantee. Align the declared MSRV with actual dep
requirements.

Author: StanMarek

.github/workflows/ci.yml

@@ -49,12 +49,12 @@ jobs:
       - run: cargo fmt --check
 
   msrv:
-    name: MSRV (1.75)
+    name: MSRV (1.86)
     runs-on: macos-latest
     steps:
       - uses: actions/checkout@v6
       - uses: dtolnay/rust-toolchain@master
         with:
-          toolchain: "1.75"
+          toolchain: "1.86"
       - uses: Swatinem/rust-cache@v2
       - run: cargo check --all-targets