build: update to nightly-2025-07-20 and use --locked for cargo-bloat

- Update rust-toolchain.toml to nightly-2025-07-20
- Add --locked flag to cargo install cargo-bloat in CI workflows
  to avoid dependency version conflicts

Author: rusty1968

.github/workflows/build-test.yml

@@ -30,7 +30,7 @@ jobs:
           sudo apt-get install -qy build-essential curl gcc-multilib gcc-riscv64-unknown-elf git
           
       - name: Install cargo-bloat
-        run: cargo install cargo-bloat
+        run: cargo install cargo-bloat --locked
 
       - name: Verify Cargo.lock is up to date
         run: |

.github/workflows/size-analysis.yml

@@ -30,7 +30,7 @@ jobs:
           sudo apt-get install -qy build-essential curl gcc-multilib gcc-riscv64-unknown-elf git
           
       - name: Install cargo-bloat
-        run: cargo install cargo-bloat
+        run: cargo install cargo-bloat --locked
 
       - name: Build current branch
         run: |

rust-toolchain.toml

@@ -1,7 +1,7 @@
 # Licensed under the Apache-2.0 license
 
 [toolchain]
-channel = "nightly-2024-09-17"
+channel = "nightly-2025-07-20"
 components = ["rust-src", "rustfmt", "clippy"]
 targets = ["thumbv7em-none-eabihf"]
 profile = "minimal"