Give listFeeds its container: Add a feed loads its Popular list again

The dialog and the Directory/Popular pane both rendered into id="popular", and
listFeeds looked it up by id, so the dialog's list landed in the pane behind it.

Fixes #1

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SZbKERNSt4vQfyGV8rvkqp

.rtk/filters.toml

@@ -0,0 +1,13 @@
+# Project-local RTK filters — commit this file with your repo.
+# Filters here override user-global and built-in filters.
+# Docs: https://github.com/rtk-ai/rtk#custom-filters
+schema_version = 1
+
+# Example: suppress build noise from a custom tool
+# [filters.my-tool]
+# description = "Compact my-tool output"
+# match_command = "^my-tool\\s+build"
+# strip_ansi = true
+# strip_lines_matching = ["^\\s*$", "^Downloading", "^Installing"]
+# max_lines = 30
+# on_empty = "my-tool: ok"