fix: add try-catch to inline hooks, fix schema drift

- Wrap JSON.parse in try-catch for all 6 inline hooks in hooks.json
  (dev-server blocker, tmux reminder, git-push reminder, doc blocker,
  PR create logger, build analysis) — previously unguarded JSON.parse
  would crash on empty/malformed stdin, preventing data passthrough
- Add config parse error logging to evaluate-session.js
- Fix plugin.schema.json: author can be string or {name,url} object,
  add version (semver pattern), homepage, keywords, skills, agents
- Fix package-manager.schema.json: add setAt (date-time) field and
  make packageManager required to match actual code behavior

schemas/package-manager.schema.json

@@ -11,7 +11,13 @@
         "yarn",
         "bun"
       ]
+    },
+    "setAt": {
+      "type": "string",
+      "format": "date-time",
+      "description": "ISO 8601 timestamp when the preference was last set"
     }
   },
+  "required": ["packageManager"],
   "additionalProperties": false
-}
+}