feat: add prune subcommand, drop archived/stale entries (#1441)

* feat: add prune subcommand, drop archived/stale entries, add container-explorer

Add a new `awesome-docker prune` subcommand that removes README entries
whose repository health status matches a configurable set (default:
archived,stale). URLs are read from the local health cache, or from a
markdown report file via --from-report when the cache is outdated.

Apply it against the issue #1439 health report to remove 5 entries
that survived the recent reorg: stitchocker, docker-consul,
blockbridge-docker-volume, docker-explorer, dockdash.

Add google/container-explorer in the Security section as the actively
maintained successor to the now-archived google/docker-explorer.

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

* golangci-lint config

* fix: address golangci-lint findings

Fixes errcheck on bufio.Writer.WriteString, gocritic rangeValCopy via
indexed loops with pointer locals, gosec G703 on user-supplied CLI
output path, noctx by switching to exec.CommandContext with a timeout
in the TUI url opener, prealloc in the scorer test, plus fieldalignment
struct reorders and golines line breaks from --fix.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude <noreply@anthropic.com>

internal/tui/tree.go

@@ -9,11 +9,11 @@ import (
 
 // TreeNode represents a node in the category tree.
 type TreeNode struct {
-	Name     string       // display name (leaf segment, e.g. "Networking")
-	Path     string       // full path (e.g. "Container Operations > Networking")
+	Name     string
+	Path     string
 	Children []*TreeNode
-	Expanded bool
 	Entries  []cache.HealthEntry
+	Expanded bool
 }
 
 // FlatNode is a visible tree node with its indentation depth.
@@ -51,14 +51,15 @@ func BuildTree(entries []cache.HealthEntry) []*TreeNode {
 	root := &TreeNode{Name: "root"}
 	nodeMap := map[string]*TreeNode{}
 
-	for _, e := range entries {
+	for i := range entries {
+		e := &entries[i]
 		cat := e.Category
 		if cat == "" {
 			cat = "Uncategorized"
 		}
 
 		node := ensureNode(root, nodeMap, cat)
-		node.Entries = append(node.Entries, e)
+		node.Entries = append(node.Entries, *e)
 	}
 
 	// Sort children at every level