feat(_checks-rs): default dev-profile debuginfo to line-tables-only

Full debuginfo dominates cargo target size (~58 of 61 GB on the
kunobi-frontend workspace) and is the main driver of the runner-pool
ephemeral-storage evictions on builder1. line-tables-only keeps
file:line backtraces at a fraction of the disk, and shrinks the kache
store and S3 transfer along with target/.

Applied to clippy/test/integration-build/build steps via a new
rust_debuginfo input (default line-tables-only, 'full' restores the
cargo default). The coverage step is exempt: tarpaulin manages its own
debuginfo flags.

Author: jleni

.github/workflows/_checks-rs.yaml

@@ -163,6 +163,10 @@ on:
         description: "Enable Rust compilation caching via kache"
         type: boolean
         default: false
+      rust_debuginfo:
+        description: "CARGO_PROFILE_DEV_DEBUG for check/test builds (coverage builds are exempt). Full debuginfo dominates target size; the default keeps file:line backtraces at a fraction of the disk. Set 'full' to restore cargo's default. Must be a valid cargo `profile.debug` value."
+        type: string
+        default: "line-tables-only"
       cache_bucket:
         description: "S3-compatible bucket name for caching (e.g., Cloudflare R2)"
         type: string
@@ -383,13 +387,15 @@ jobs:
         if: inputs.enable_linting
         env:
           CARGO_INCREMENTAL: ${{ inputs.use_rust_cache && '0' || '' }}
+          CARGO_PROFILE_DEV_DEBUG: ${{ inputs.rust_debuginfo }}
           RUSTFLAGS: "-D warnings"
         run: ${{ inputs.lint_command }}
 
       - name: Run tests
         if: inputs.enable_tests && !inputs.enable_coverage
         env:
           CARGO_INCREMENTAL: ${{ inputs.use_rust_cache && '0' || '' }}
+          CARGO_PROFILE_DEV_DEBUG: ${{ inputs.rust_debuginfo }}
         run: ${{ inputs.test_command }} ${{ inputs.test_args }}
 
       - name: Run tests with coverage
@@ -402,6 +408,7 @@ jobs:
         if: inputs.enable_integration_tests && inputs.integration_build_command != ''
         env:
           CARGO_INCREMENTAL: ${{ inputs.use_rust_cache && '0' || '' }}
+          CARGO_PROFILE_DEV_DEBUG: ${{ inputs.rust_debuginfo }}
         run: ${{ inputs.integration_build_command }}
 
       - name: Run integration tests
@@ -412,6 +419,7 @@ jobs:
         if: inputs.enable_build
         env:
           CARGO_INCREMENTAL: ${{ inputs.use_rust_cache && '0' || '' }}
+          CARGO_PROFILE_DEV_DEBUG: ${{ inputs.rust_debuginfo }}
         run: ${{ inputs.build_command }}
 
       - name: Security audit with cargo-audit