fix: orch run from worktree creates separate vault, runs not visible from main repo

[proboscis]

Problem

When running orch run from a git worktree, the run is not visible when running orch ps from the main repository.

Root Cause

The config uses vault: . which is a relative path. When orch runs from a worktree:

1. vault: . resolves to the worktree directory
2. A new .orch/ directory is created in the worktree
3. A separate daemon starts for the worktree's vault
4. Runs are tracked in the worktree's vault, not the main repo's vault

Reproduction

# From main repo
cd ~/repos/orch
orch ps  # Shows runs

# From a worktree  
cd .git-worktrees/gh#285/...
orch run gh#287  # Creates run

# Back to main repo
cd ~/repos/orch
orch ps  # Run gh#287 NOT visible!

# From worktree
cd .git-worktrees/gh#285/...
orch ps  # Run gh#287 IS visible

Evidence

=== Worktree .orch ===
daemon.sock  daemon.pid  ...

=== Main repo .orch ===
daemon.sock  daemon.pid  ...  (different daemon!)

Suggested Fix

When in a git worktree, orch should detect this and use the main repo's vault instead of creating a new one. Options:

1. Resolve vault: . to the git root (not worktree root)
2. Follow .git file in worktrees to find the main repo
3. Use absolute path in config instead of relative

Impact

• Runs started from worktrees are invisible from main repo
• Multiple daemons running for same logical project
• Confusing UX when switching between main repo and worktrees