Feature: default worktree hydration for gitignored agent-runtime config

## Feature Request

Worktrees Orca spawns don't carry over gitignored, untracked files — most notably local/secret overrides for agent runtime config (e.g. `.claude/settings.local.json`, `.env*`), so agents launched inside an Orca worktree can lose project-specific local config that was intentionally kept out of git.

**Use case:**
Committed config (`.claude/settings.json`, skills, hooks, `mcp.json` without secrets) already flows into worktrees via git — no issue there. The gap is local overrides some teams gitignore on purpose (e.g. MCP server configs with embedded API keys/tokens). Opening a worktree in Orca and launching an agent, that local slice is missing, so the agent falls back to global-only config. Today's workaround is a manual post-worktree-creation shell step in project settings to copy these files over, which every user has to hand-roll per project.

**Proposed behavior:**
- Built-in "hydrate worktree" step, off by default, with a user-configurable copy list for gitignored paths (defaults could suggest `.claude/settings.local.json`, `.env*`)
- Runs after `git worktree add`, before agent launch
- Committed config needs no special handling — this only fills the gitignored-local-override gap
- Prior art: `worktrunk` CLI's `wt step copy-ignored` solves this exact problem — usable as reference implementation
- Should compose with existing post-worktree-creation setup-commands hook rather than replace it