update toolchain to nightly-2024-07-30 (#322)

this PR changes the toolchain to use `nightly-2024-07-30` and fixes
`platforms/x86_64` dependencies so it uses root's `Cargo.toml` patch
section for maitake crates.


closes #323 

obsoletes #306

TODO for reviewers (roughly ordered by assumed importance):
- [ ] ensure `target_has_atomic` is the right fix (
a9e59b1 )
- [ ] [warning: transmute used without annotations -->
platforms/allwinner-d1/d1-core/src/drivers/smhc.rs:521:58](https://github.com/tosc-rs/mnemos/blob/update-toolchain/platforms/allwinner-d1/d1-core/src/drivers/smhc.rs#L521)
- [ ] [interior mutable const
lint](https://github.com/tosc-rs/mnemos/blob/80928e4f13d97ac4e21655ff19b82fa0e5fc2e43/source/spitebuf/src/lib.rs#L182)
- [ ] `VAddr::of(&DOUBLE_FAULT_STACK)` ( 1aecece ) - can't use clippy's
suggested `ptr::addr_of!` with pinned mycelium (probably best to create
dedicated issue)
- [ ] warning: struct `GrantWriter` is never constructed:
[platforms/allwinner-d1/d1-core/src/drivers/uart.rs:27:8](https://github.com/tosc-rs/mnemos/blob/80928e4f13d97ac4e21655ff19b82fa0e5fc2e43/platforms/allwinner-d1/d1-core/src/drivers/uart.rs#L28)
- [ ] warning: struct `GrantWriter` is never constructed:
[platforms/esp32c3-buddy/src/drivers/usb_serial.rs:16:8](https://github.com/tosc-rs/mnemos/blob/update-toolchain/platforms/esp32c3-buddy/src/drivers/usb_serial.rs#L16)
- [ ] warning: struct `GrantWriter` is never constructed:
[platforms/esp32c3-buddy/src/drivers/uart.rs:21:8](https://github.com/tosc-rs/mnemos/blob/update-toolchain/platforms/esp32c3-buddy/src/drivers/uart.rs#L21)
- [ ] warning: trait `TryFromBits` is never used:
[platforms/allwinner-d1/d1-core/src/plic.rs:186:7](https://github.com/tosc-rs/mnemos/blob/update-toolchain/platforms/allwinner-d1/d1-core/src/plic.rs#L186)
- [ ] warning: struct `SingleThreadedLinkedListAllocator` is never
constructed:
[source/alloc/src/heap.rs:288:12](https://github.com/tosc-rs/mnemos/blob/update-toolchain/source/alloc/src/heap.rs#L288)

---------

Co-authored-by: Anatol Ulrich <[email protected]>
Co-authored-by: Eliza Weisman <[email protected]>

.github/workflows/ci.yml

@@ -101,7 +101,7 @@ jobs:
     - name: install nextest
       uses: taiki-e/install-action@v2
       with:
-        tool: cargo-nextest@0.9.61
+        tool: cargo-nextest@latest
     - uses: extractions/setup-just@v1
     - name: just test
       run: just test