fix: resolve 25 pre-publish blockers

- postinstall.mjs: fix alias package detection
- migrate-legacy-plugin-entry: dedupe + regression tests
- task_system: default consistency across runtime paths
- task() contract: consistent tool behavior
- runtime model selection, tool cap, stale-task cancellation
- recovery sanitization, context-limit gating
- Ralph semantic DONE hardening, Atlas fallback persistence
- native-skill description/content, skill path traversal guard
- publish workflow: platform awaited via reusable workflow job
- release: version edits reapplied before commit/tag
- JSONC plugin migration: top-level plugin key safety
- cold-cache: user fallback models skip disconnected providers
- docs/version/release framing updates

Verified: bun test (4599 pass), tsc --noEmit clean, bun run build clean

assets/oh-my-opencode.schema.json

@@ -4885,6 +4885,11 @@
       "additionalProperties": false
     },
     "git_master": {
+      "default": {
+        "commit_footer": true,
+        "include_co_authored_by": true,
+        "git_env_prefix": "GIT_MASTER=1"
+      },
       "type": "object",
       "properties": {
         "commit_footer": {
@@ -5035,5 +5040,8 @@
       }
     }
   },
+  "required": [
+    "git_master"
+  ],
   "additionalProperties": false
 }