fix: extend git-root collection fix to codex/opencode skills; async session-end (#331)

The git-root collection mismatch fixed in #330 for the Claude Code
plugin also affects the Codex and OpenCode plugins — their
memory-recall skills call derive-collection.sh without arguments
(defaults to pwd) while the hook/install scripts use the git repo
root. Mirror the same fix so all three plugins converge on the
same collection regardless of launch directory.

Also mark SessionEnd async in the Claude Code hooks.json: the hook
only performs watch-process cleanup (stop_watch + orphan sweep),
which the user does not need to wait for. This removes up to a few
hundred milliseconds of perceived exit latency without changing
behavior.

Signed-off-by: Cheney Zhang <chen.zhang@zilliz.com>

Author: zc277584121

plugins/claude-code/hooks/hooks.json

@@ -41,6 +41,7 @@
           {
             "type": "command",
             "command": "bash ${CLAUDE_PLUGIN_ROOT}/hooks/session-end.sh",
+            "async": true,
             "timeout": 10
           }
         ]

plugins/codex/skills/memory-recall/SKILL.md

@@ -9,7 +9,7 @@ You are performing memory retrieval for memsearch. Search past memories and retu
 
 Determine the collection name by running:
 ```
-bash __INSTALL_DIR__/scripts/derive-collection.sh
+bash -c 'root=$(git rev-parse --show-toplevel 2>/dev/null || true); if [ -n "$root" ]; then bash __INSTALL_DIR__/scripts/derive-collection.sh "$root"; else bash __INSTALL_DIR__/scripts/derive-collection.sh; fi'
 ```
 
 ## Steps

plugins/opencode/skills/memory-recall/SKILL.md

@@ -8,7 +8,7 @@ You are a memory retrieval agent for memsearch. Your job is to search past memor
 
 ## Project Collection
 
-Collection: !`bash __INSTALL_DIR__/scripts/derive-collection.sh`
+Collection: !`bash -c 'root=$(git rev-parse --show-toplevel 2>/dev/null || true); if [ -n "$root" ]; then bash __INSTALL_DIR__/scripts/derive-collection.sh "$root"; else bash __INSTALL_DIR__/scripts/derive-collection.sh; fi'`
 
 ## Your Task