#2908 Run from a git worktree: definitions from the worktree, state from the shared repo

What happens

swamp treats one directory as both the source of definitions (workflows, models) and the home of state (.swamp/). --repo-dir sets both at once.

A git worktree splits them. The definitions you want are the worktree's (the change under work), but the state lives in the main checkout's .swamp/, since the worktree is not an initialized swamp repo. So from a worktree you pass --repo-dir <main checkout>, and swamp then also reads definitions from the main checkout.

To get the worktree's workflows back you set SWAMP_WORKFLOWS_DIR to an absolute path into the worktree. A relative path resolves against --repo-dir, so it silently runs the main checkout's workflows instead.

Why it matters

swamp-extensions' pre-PR verification (verification/workflow-verify*.yaml) must run the change's own workflow files: build-attestation and CI's validate-attestation pin them. Every agent session works from a worktree, so issue-lifecycle and the gatorwalk-factory verify stage both carry hand-written instructions to build an absolute path and add --repo-dir. Getting it wrong fails late, at attestation, not at the run.

gatorwalk-factory works around it for now (swamp-club #2773) by computing both paths with git in the stage command, which couples the factory definition to git.

Fix direction

Preferred: a worktree (or any directory) can be a swamp repo whose state lives elsewhere. Definitions come from the directory you run in; models, data and run history come from the shared repo. No --repo-dir, no SWAMP_WORKFLOWS_DIR. Worth checking first whether a datastore configuration can already point a worktree at the main checkout's state.

Fallback: resolve a relative SWAMP_WORKFLOWS_DIR against the working directory rather than --repo-dir. That removes the absolute path; --repo-dir is still needed.

Done when

From a worktree of a swamp repo, swamp workflow run <name> runs the worktree's definition of that workflow and records the run in the shared repo's state, with no absolute paths supplied by hand.