feat(daemon): agent-driven repo checkout with bare clone cache

Agents now decide which repo to use based on issue context and check out
repos on demand via `multica repo checkout <url>`. Workspace repos are
cached locally as bare clones for fast worktree creation.

Key changes:
- Add repocache package for bare clone management (clone, fetch, worktree)
- Add `multica repo checkout` CLI command that talks to local daemon
- Add POST /repo/checkout endpoint on daemon health server
- Pass workspace repos metadata through register + task claim responses
- Remove pre-created worktrees from execenv (workdir starts empty)
- Update CLAUDE.md template to instruct agents to use `multica repo checkout`
- Pass MULTICA_DAEMON_PORT, WORKSPACE_ID, AGENT_NAME, TASK_ID env vars to agent

server/internal/cli/config.go

@@ -46,6 +46,7 @@ func (c *CLIConfig) RemoveWatchedWorkspace(id string) bool {
 	return false
 }
 
+
 // CLIConfigPath returns the default path for the CLI config file.
 func CLIConfigPath() (string, error) {
 	home, err := os.UserHomeDir()