Dock the results table in the bottom panel

createWebviewPanel only ever lives in the editor area, so the table could
not be dragged next to Terminal / Problems. A WebviewView can, and it can
also be dragged to either side bar.

- Extract ResultsView: the table's html, messaging, row building and
  navigation, independent of what hosts the webview. ReferencePanel keeps
  hosting it in an editor group; ReferenceViewProvider hosts it in a
  contributed panel view container. Results that arrive before the docked
  view has been resolved are queued and applied on resolve.
- coloredReferences.panelLocation selects the placement: bottom (default),
  beside, or below. "below" makes the editor row first so the table is wide
  and short, which suits the column layout better than a tall narrow group.
- sourceColumn() now ignores editors with no view column, so opening a
  reference from the docked view lands in a real editor group.
- toggleView and the refresh button work from either host.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

package.json

@@ -18,7 +18,9 @@
     "dotnet",
     "visual studio"
   ],
-  "activationEvents": [],
+  "activationEvents": [
+    "onView:coloredReferences.resultsView"
+  ],
   "main": "./out/extension.js",
   "contributes": {
     "commands": [
@@ -75,7 +77,7 @@
         "command": "coloredReferences.toggleView",
         "key": "ctrl+alt+shift+f12",
         "mac": "cmd+alt+shift+f12",
-        "when": "resourceScheme == colored-refs || activeWebviewPanelId == coloredReferences.results"
+        "when": "resourceScheme == colored-refs || activeWebviewPanelId == coloredReferences.results || view == coloredReferences.resultsView"
       }
     ],
     "menus": {
@@ -109,7 +111,7 @@
         },
         {
           "command": "coloredReferences.toggleView",
-          "when": "resourceScheme == colored-refs || activeWebviewPanelId == coloredReferences.results"
+          "when": "resourceScheme == colored-refs || activeWebviewPanelId == coloredReferences.results || view == coloredReferences.resultsView"
         }
       ]
     },
@@ -143,8 +145,42 @@
           ],
           "default": "document",
           "description": "Which view Find All References (Colored) opens."
+        },
+        "coloredReferences.panelLocation": {
+          "type": "string",
+          "enum": [
+            "bottom",
+            "beside",
+            "below"
+          ],
+          "enumDescriptions": [
+            "Dock the results table in the bottom panel, beside Terminal and Problems. Drag it to a side bar if you prefer.",
+            "Open the results table in an editor group beside the current one.",
+            "Open the results table in an editor group below the current one, so it is wide and short."
+          ],
+          "default": "bottom",
+          "description": "Where the results panel opens."
         }
       }
+    },
+    "viewsContainers": {
+      "panel": [
+        {
+          "id": "coloredReferences",
+          "title": "References",
+          "icon": "media/references-dark.svg"
+        }
+      ]
+    },
+    "views": {
+      "coloredReferences": [
+        {
+          "id": "coloredReferences.resultsView",
+          "name": "References",
+          "type": "webview",
+          "contextualTitle": "References"
+        }
+      ]
     }
   },
   "scripts": {