fix: restore /last30days slash command on Claude Code v2.1.105+ (#261)

Two regressions were silently breaking /last30days for every user:

1. plugin.json declared "skills": ["./"], which newer Claude Code
   rejects with "Path escapes plugin directory: ./ (skills)". The
   skill loader refused to register the command, so /last30days
   returned "Unknown command" even though /plugin list showed the
   plugin as installed. Fix: "skills": ["skills"] so the loader
   scans the real subdirectory.

2. marketplace.json pinned "version": "3.0.0" while plugin.json
   advertised "3.0.1". The /plugin resolver used the marketplace
   version and could install a phantom user-scope copy at a stale
   SHA alongside the correct project-scope install, creating
   duplicate skill-name collisions. Both manifests now agree on
   3.0.2.

Prior attempt: commit 93fbed2 fixed (1) before but got reverted.
This lands both fixes together in a tagged release so users can
/plugin update to recover.

Recovery for affected users is in CHANGELOG.md under 3.0.2.

Co-authored-by: Matt Van Horn <455140+mvanhorn@users.noreply.github.com>

.claude-plugin/marketplace.json

@@ -10,7 +10,7 @@
     {
       "name": "last30days",
       "description": "Research any topic across Reddit, X, YouTube, TikTok, Instagram, HN, Polymarket, GitHub, and 5+ more sources.",
-      "version": "3.0.0",
+      "version": "3.0.2",
       "author": {
         "name": "Matt Van Horn",
         "url": "https://github.com/mvanhorn"

.claude-plugin/plugin.json

@@ -1,6 +1,6 @@
 {
   "name": "last30days",
-  "version": "3.0.1",
+  "version": "3.0.2",
   "description": "Research any topic across Reddit, X, YouTube, TikTok, Instagram, Hacker News, Polymarket, GitHub, and 5+ more sources. AI agent scores by upvotes, likes, and real money - not editors.",
   "author": {
     "name": "Matt Van Horn",
@@ -11,6 +11,6 @@
   "repository": "https://github.com/mvanhorn/last30days-skill",
   "license": "MIT",
   "keywords": ["research", "reddit", "twitter", "youtube", "tiktok", "instagram", "trends", "prompts", "polymarket", "github", "perplexity", "threads", "pinterest", "eli5", "hacker-news"],
-  "skills": ["./"],
+  "skills": ["skills"],
   "hooks": {}
 }