deb,quirks: generic dependency rules for build-dep workarounds

The resolute linux and linux-riscv controls declare llvm-21-dev
unqualified while their other llvm pieces are :native, so the dpkg
cross rules resolve it against the host architecture — whose
dependency closure needs python3:riscv64, conflicting with the
python3 the control itself declares :native. No resolver can install
that set; sbuild fails on it identically.

Give the deb quirks a dependencies rule set rather than a one-off
native-qualification knob: replace rewrites a declared dependency by
name with a full dependency string (qualifier, version and
restrictions included), inject adds dependencies resolved as if
declared, drop ignores declared ones. Entries are scoped by series so
they can be dropped when the upstream packaging catches up, and rule
names that match nothing are warned about so stale quirks surface.

Ship the llvm-21-dev entry for the resolute kernels: resolve it as
llvm-21-dev:native, keeping the declared <!stage1> restriction.

src/deb/local.rs

@@ -265,6 +265,7 @@ pub async fn build(
         package,
         version,
         arch,
+        series,
         package_dir_str,
         build_root,
         cross,
@@ -564,6 +565,7 @@ fn install_build_dependencies(
     package: &str,
     version: &str,
     arch: &str,
+    series: &str,
     package_dir: &str,
     build_root: &str,
     cross: bool,
@@ -610,10 +612,13 @@ fn install_build_dependencies(
         union: false,
         build_dep: true,
     };
-    let clauses: Vec<Vec<PkgRelation>> = Deps::parse(&deps_value, &parse_opts)?
+    let mut clauses: Vec<Vec<PkgRelation>> = Deps::parse(&deps_value, &parse_opts)?
         .clauses()
         .map(<[PkgRelation]>::to_vec)
         .collect();
+    // Package-specific workarounds (see data/quirks.yml), before anything
+    // derives candidate queries or install specs from the clauses.
+    crate::quirks::apply_dependency_quirks(package, series, &mut clauses, &parse_opts)?;
     let conflict_clauses: Vec<Vec<PkgRelation>> = if conflicts_value.trim().is_empty() {
         Vec::new()
     } else {