Fix borgmatic PostgreSQL backup and update backup sources (#21)

## Summary
- Fix PostgreSQL backup failure by adding explicit `pg_dump_command` path (was failing with "pg_dump: command not found" in LaunchAgent)
- Remove `~/code/3rd/kiwix-tools` from backups (was just symlinks to ZIM archives in transmission)
- Enable Loki log backup by removing from exclude_patterns

## Deployment and Testing
- [x] Dry run with `--check --diff` shows expected changes
- [ ] Deploy with `mise run provision-indri -- --tags borgmatic`
- [ ] Verify config deployed: `ssh indri 'cat ~/.config/borgmatic/config.yaml'`
- [ ] Run manual backup to test: `ssh indri 'mise x -- borgmatic create --verbosity 1'`
- [ ] Verify PostgreSQL dump succeeds (no "pg_dump: command not found" error)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Reviewed-on: https://forge.tail8d86e.ts.net/eblume/blumeops/pulls/21

ansible/playbooks/indri.yml

@@ -91,6 +91,8 @@
       tags: kiwix
     - role: borgmatic
       tags: borgmatic
+    - role: borgmatic_metrics
+      tags: borgmatic_metrics
     - role: forgejo
       tags: forgejo
     - role: devpi