feat(experimental): add Claude Code mods bridge

Add @deepseek-ai/dsh-experimental-claude-code-mods, an alpha bridge that
loads Claude Code mods (plugin directories whose hooks/hooks.json names a
hooks module), runs register(on, options) unchanged, and raises the mod
events from harness extension points: session.start on agent/created,
prompt.submit and turn.start on agent/pre-step, tool.call around
tools/execute, turn.complete on turn/end, session.end on agent/disposed,
and command.run from registered commands. The $ mods API is served over
composed services (commands, tools, user-questions, fs, subprocess,
storage domain, projections); unserved members fail by name.

Includes a middleware chain with Claude Code's failure rules and budget
clock, a claude-code/testing-style test kit, fixtures from the mods
tutorial, full-loop and Loader composition tests, the attribution-only
claude-code-mods message source with its persistence record, and the
regenerated catalogs.

packages/experimental/README.md

@@ -33,6 +33,7 @@ Experimental prototypes may change their contracts and carry no support promise.
 | [`agent-team`](agent-team/README.md) | Named teammates with durable messages and a shared task board | `ctx.agentTeams` |
 | [`client-ui-agent-team`](client-ui-agent-team/README.md) | Team roster, task board, and teammate navigation for Web | — |
 | [`auto-review`](auto-review/README.md) | Explicit Web layer for same-model review before each native or PTC inner tool call | — |
+| [`claude-code-mods`](claude-code-mods/README.md) | Load Claude Code mods and run their hook chains on harness extension points | — |
 | [`ptc-runtime-python`](ptc-runtime-python/README.md) | CPython subprocess backend for the PTC execution seam | `ctx.ptcRuntime` |
 | [`computer-use-cua-driver-mcp`](computer-use-cua-driver-mcp/README.md) | Use an installed Cua Driver through MCP | `ctx.computerUse` |
 | [`computer-use-cua-driver-native`](computer-use-cua-driver-native/README.md) | Embed the Cua Driver native npm runtime | `ctx.computerUse` |