Bug 1: capability loaders in src/discovery/builtin.ts only walked
.omp/ and ~/.omp/agent/, so extension packages registered via
extensions: in settings or --extension on the CLI shipped their
skills/, hooks/pre|post/, tools/, commands/, rules/, prompts/, and
.mcp.json silently — the docs at omp.sh/docs/extension-authoring
advertise the opposite. Add a new omp-plugins discovery provider that
scans every configured extension package directory for those
sub-trees, plus a small omp-extension-roots helper that resolves the
union of settings-driven and CLI-injected roots. main.ts injects CLI
extension paths via injectOmpExtensionCliRoots before any capability
load.
Bug 2: install was never registered as a top-level subcommand, so
`omp install ./my-extension` was rewritten to `launch install
./my-extension` and forwarded to the LLM as an initial prompt. Add a
top-level install command that routes local paths to plugin link and
remote specs to plugin install. Extract the command table into
src/cli-commands.ts so tests can introspect registered subcommands
without triggering cli.ts's top-level await.
Fixes#1496
roboomp