Move version-less drop reconciliation into the walk, harden the name guards

The shared walk now defers every version-less skip and reconciles after
emit against the final resolution set (request keys, resolved manifest
names, and backend.provides(name) per name), so drop visibility is
correct for every backend by construction instead of by a comment-level
contract, and the arduino backend's duplicate pending_drops pass and its
short-name suppression heuristics are deleted. The provides lambda
applies _is_safe_library_name so an unsafe manifest name is simply not
provided, and the guard also rejects drive-colon names that would
escape the tree on Windows.

tests/unit_tests/test_platformio_library.py

@@ -620,7 +620,10 @@ def test_versionless_dependency_without_provider_warns(
         {"esphome/A": {"name": "A", "dependencies": [{"name": "Hash"}]}},
     )
     convert_libraries([Library("esphome/A", None, None)], _backend())
-    assert "'Hash' of esphome/A has no version to resolve" in caplog.text
+    assert (
+        "Hash of esphome/A has no version to resolve and nothing provides it"
+        in caplog.text
+    )
 
 
 def test_walk_warns_for_nonplatform_invalid_library(
@@ -678,4 +681,31 @@ def test_versionless_url_ish_dependency_name_warns_cleanly(
         {"esphome/A": {"name": "A", "dependencies": [{"name": "file://"}]}},
     )
     convert_libraries([Library("esphome/A", None, None)], _backend())
-    assert "'file://' of esphome/A has no version to resolve" in caplog.text
+    assert (
+        "file:// of esphome/A has no version to resolve and nothing provides it"
+        in caplog.text
+    )
+
+
+def test_versionless_dependency_matching_resolved_manifest_name_stays_quiet(
+    tmp_path, monkeypatch, caplog: pytest.LogCaptureFixture
+) -> None:
+    """A bare dependency name satisfied by a component requested under an
+    owner-qualified spec (manifest names match) is not a drop; a nameless
+    entry is skipped without a reconciliation warning."""
+    _patch_download_with_manifests(
+        monkeypatch,
+        tmp_path,
+        {
+            "esphome/A": {
+                "name": "A",
+                "dependencies": [{"name": "B"}, {"version": "1.0"}],
+            },
+            "esphome/B": {"name": "B"},
+        },
+    )
+    convert_libraries(
+        [Library("esphome/A", None, None), Library("esphome/B", None, None)],
+        _backend(),
+    )
+    assert "has no version to resolve" not in caplog.text