nfpm.native_libs: regen elfdeps.lock and fix plugin registration (#22903)

#22890 changed the interpreter constraints to include python 3.14. I
missed including that in #22873 (which was merged after #22890),
so this PR regenerates `elfdeps.lock` with the bumped ICs.

#22873 also missed registering the
`pants.backend.experimental.nfpm.native_libs` backend, which I
discovered when looking for script deps in the output of:
```
pants dependencies --transitive src/python/pants:pants-packaged | less
```

Author: cognifloyd

src/python/pants/backend/nfpm/native_libs/elfdeps/elfdeps.lock

@@ -58,14 +58,14 @@
   "only_wheels": [],
   "overridden": [],
   "path_mappings": {},
-  "pex_version": "2.59.1",
-  "pip_version": "25.2",
+  "pex_version": "2.69.2",
+  "pip_version": "25.3",
   "prefer_older_binary": false,
   "requirements": [
     "elfdeps>=0.2.0"
   ],
   "requires_python": [
-    "CPython<3.14,>=3.10"
+    "CPython<3.15,>=3.10"
   ],
   "resolver_version": "pip-2020-resolver",
   "style": "universal",

src/python/pants/backend/nfpm/native_libs/elfdeps/elfdeps.lock.metadata

@@ -1,7 +1,7 @@
 {
-  "version": 4,
+  "version": 5,
   "valid_for_interpreter_constraints": [
-    "CPython<3.14,>=3.10"
+    "CPython<3.15,>=3.10"
   ],
   "generated_with_requirements": [
     "elfdeps>=0.2.0"
@@ -12,5 +12,6 @@
   "no_binary": [],
   "excludes": [],
   "overrides": [],
+  "sources": [],
   "description": "This lockfile was generated by Pants. To regenerate, run: ./pants run build-support/bin/generate_builtin_lockfiles.py"
 }

src/python/pants/backend/nfpm/native_libs/elfdeps/subsystem.py

@@ -36,7 +36,7 @@ class Elfdeps(PythonToolBase):
     default_main = ConsoleScript("elfdeps")
     default_requirements = ["elfdeps>=0.2.0"]
 
-    default_interpreter_constraints = ["CPython>=3.10,<3.14"]
+    default_interpreter_constraints = ["CPython>=3.10,<3.15"]
     register_interpreter_constraints = True
 
     default_lockfile_resource = (_ELFDEPS_PACKAGE, "elfdeps.lock")

src/python/pants/bin/BUILD

@@ -59,6 +59,7 @@ target(
         "src/python/pants/backend/experimental/kotlin/lint/ktlint",
         "src/python/pants/backend/experimental/makeself",
         "src/python/pants/backend/experimental/nfpm",
+        "src/python/pants/backend/experimental/nfpm/native_libs",
         "src/python/pants/backend/experimental/openapi",
         "src/python/pants/backend/experimental/openapi/codegen/java",
         "src/python/pants/backend/experimental/openapi/codegen/python",