fix: adopt new worktree when a project repository is moved

[jonathangn]

Problem

When a project's repository is moved or renamed on disk (e.g. the folder is moved to a parent directory), opencode keeps using the old worktree path:

• Project.fromDirectory always keeps existing.worktree for existing (non-global) projects, even when that path no longer exists. The resolved new checkout is only ever added to sandboxes, never adopted as the project's worktree.
• InstanceStore.boot uses the requested directory verbatim as the instance/session directory. If a client passes a stale path (as the desktop does from its persisted project state), the instance boots with a non-existent directory.

The result: "New conversation" fails with ENOENT / FileSystem.realPath errors until the user manually edits the database. Repros happen whenever the repo root is moved up to its parent (e.g. G:/.../AlgoTrading/EA Admirals -> G:/.../AlgoTrading), so the old worktree is now a dead child of the new git root.

Fix

Two complementary server-side changes:

1. Project.fromDirectory (packages/opencode/src/project/project.ts): if the project's canonical worktree no longer exists on disk and the repository still resolves to a valid checkout, adopt the resolved git worktree (data.directory) as the new canonical worktree. Existing sessions rooted at the old worktree are re-pointed to the new directory, so old conversations keep working.
2. InstanceStore.boot (packages/opencode/src/project/instance-store.ts): when the requested directory does not exist but fromDirectory resolved it to a non-global git project, boot the instance in the resolved worktree (result.sandbox) instead of the stale path. This makes both new sessions and loading old sessions succeed even when a client passes a path that no longer exists.

Tests

• Project.fromDirectory with worktrees > adopts a moved checkout as the project worktree when the original is gone — moves a repo and asserts the project adopts the new worktree.
• InstanceStore > boots into the resolved worktree when the requested directory no longer exists — loads an instance at a non-existent child of a git root and asserts it boots into the resolved worktree.

Both new tests pass; the existing project and instance-store suites pass (47/47). tsgo --noEmit and oxlint are clean on the touched files.

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[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Found potential related PRs:

1. PR fix(opencode): recover projects moved to a new path #38584 - fix(opencode): recover projects moved to a new path

   • fix(opencode): recover projects moved to a new path #38584
   • Why related: This directly addresses recovering projects that have been moved to a new path, which is closely related to the worktree adoption logic in PR fix: adopt new worktree when a project repository is moved #42933.

2. PR fix (core): Multiple clones of same repo are different projects #35311 - fix (core): Multiple clones of same repo are different projects

   • fix (core): Multiple clones of same repo are different projects #35311
   • Why related: Concerns project repository tracking and disambiguation, which may relate to how projects are resolved when repositories are moved or reorganized.

I recommend checking if PR #38584 was a previous attempt at this issue or if there's overlap in the solution approach.

[jonathangn]

Closing this in favor of existing work: this duplicates #38584 (same fix, same files, more thorough) and #35311 (the maintainer-preferred approach). Nothing lost — the regression tests and analysis are preserved in this branch (fix/moved-repo-worktree) and in the PR history if anyone wants to reuse them.