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markdown report file via --from-report when the cache is outdated.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/checker/github_test.go

@@ -34,7 +34,14 @@ func TestExtractGitHubRepo(t *testing.T) {
 		}
 		if ok {
 			if owner != tt.owner || name != tt.name {
-				t.Errorf("ExtractGitHubRepo(%q) = (%q, %q), want (%q, %q)", tt.url, owner, name, tt.owner, tt.name)
+				t.Errorf(
+					"ExtractGitHubRepo(%q) = (%q, %q), want (%q, %q)",
+					tt.url,
+					owner,
+					name,
+					tt.owner,
+					tt.name,
+				)
 			}
 		}
 	}