fix(core): normalize tool schemas for Anthropic, add toolChoice=auto; feat(summon): agent definition support; docs: cc/ research findings

- registry.ts: add normalizeForAnthropic() to strip , additionalProperties, default, nullable from zodToJsonSchema output so Anthropic doesn't silently reject tool definitions
- agent.ts: add toolChoice=auto for Claude OAuth to prevent Opus thinking forever without calling tools
- summon.ts: add agentSlug parameter, build agents catalog in description, add toAvailableAgents helper
- agent-manager.ts: wire agent definition loading into spawnChildAgent, agent model fallback
- loader.ts: export loadAgent, expandAgentToolNames, getAgentDirPaths; add getAgentDirPaths for permission gate
- agent.ts: auto-allow read-only tools in agent definition directories
- packaging/PKGBUILD: exclude ARM64 prebuilds from x86_64 package
- cc/: research findings on Claude Opus tool calling issues
- tests: loader tests, summon tool tests

1 files changed, 2 insertions, 0 deletions

diff --git a/packaging/PKGBUILD b/packaging/PKGBUILD
index 4ac87a8..a514eb5 100644
--- a/packaging/PKGBUILD
+++ b/packaging/PKGBUILD
@@ -91,8 +91,10 @@ package_dispatch() {
 	install -Dm644 packages/frontend/package.json "${optdir}/packages/frontend/package.json"
 
 	# Runtime node_modules (preserve symlinks for bun workspaces)
+	# Exclude prebuilt ARM64 .node binaries — strip (x86_64 host) can't process them.
 	install -dm755 "${optdir}/node_modules"
 	cp -a node_modules/. "${optdir}/node_modules/"
+	find "${optdir}/node_modules" -path '*/prebuilds/linux-arm64/*.node' -delete
 
 	# Root manifest + lockfile
 	install -Dm644 package.json "${optdir}/package.json"