fix: resolve the issue store from the project, not the plugin

`issue.store_root` and `_gitea.PAYLOAD_ROOT` were anchored on `__file__`, on
the reasoning that where an installation keeps its files is a fact about the
installation. That holds for an installation and not for a store.

Installed, the plugin therefore resolved every project's issues inside its own
directory — and a plugin cache is versioned, so the store moved on each
update:

    ~/.claude/plugins/cache/tea/tea/2.0.0/tmp/issues   5 files, 2 origin: local
    ~/.claude/plugins/cache/tea/tea/2.1.0/tmp/issues   12 files
    ~/.claude/plugins/cache/claude-skills/tea/2.2.0/   empty, the current one

Issues written from one project were invisible from the next, and an `origin:
local` file — which IS the issue, the only copy — was stranded a version bump
at a time. Two of them were.

The store is a fact about the project, exactly as the login pin is. So the
anchor is now an explicit marker an operator creates, `.tea/`, searched for up
from $CLAUDE_PROJECT_DIR and then cwd — the pin's order, so the two cannot
disagree about which project this is. Inferred markers were tried and are worse
than useless here: `.git` is in every clone including this plugin's own, and
the agents-sync hook writes an AGENTS.md next to every AGENTS.md, so the plugin
root always carried one and cwd never got a turn.

With no marker anywhere, `store_root()` is None and every entry point reports
which directories it searched. A store in a plausible-looking directory is the
failure this replaces, so nothing falls back to one.

- `.tea/` holds the store and the transport's scratchpad: `.tea/issues`,
  `.tea/payload`. One marker, one walk, one gitignore line.
- `issue_init.py` creates it, moves an old `tmp/issues` store in rather than
  copying, adds `.tea/` to `.gitignore`, and refuses to pick a winner when both
  sides hold the same file name.
- A linked worktree has no marker — it is gitignored — and reaches the main
  checkout's store by the hop the pin already took.
- `parents`, `gitdir_of` and `main_worktree` move from `pin.py` into the domain
  and `pin.py` imports them. The domain depends on nothing, so it is the layer
  all three callers can borrow from, and the walk stays written once: the
  guard, the transport and the store cannot disagree about a directory.

The suite stopped copying the script layers into its fixtures. That is what hid
this: with the scripts inside the fixture, the installation and the project
were the same directory. They are now deliberately far apart, and a regression
test asserts the plugin tree gains no files when commands run against a project
somewhere else.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

plugins/tea/skills/sync/scripts/pull.py

@@ -10,7 +10,7 @@ once Gitea has confirmed it, so pulling is not a refresh of a copy you kept —
 it is how the copy comes to exist. It lands under the SAME slug it had before,
 even after a rename in the web UI and even on a machine that has never seen the
 issue: the slug travels in the body as `<!-- tea:id … -->`, and
-tmp/issues/.remote.json indexes it by number. See `id_for` for the order those
+.tea/issues/.remote.json indexes it by number. See `id_for` for the order those
 are consulted in. The marker itself is stripped out of what is written to disk.
 
 Two ways to name what to pull:
@@ -55,7 +55,7 @@ writes nothing at all, so there is no write to bound and its `--limit` means
 what it says — how many lines to print.
 
 Comments ride along by default, in both modes and for every issue written:
-the thread lands in tmp/issues/<id>.comments.md, beside the issue. It costs
+the thread lands in .tea/issues/<id>.comments.md, beside the issue. It costs
 nothing when there is nothing to fetch — the payload already carries the
 comment count, so an issue with none makes no request, and a file left over
 from an earlier pull is deleted. An absent file therefore means "no comments",
@@ -218,7 +218,7 @@ def main():
                     help="skip issues already on disk instead of refetching")
     ap.add_argument("--repo", help="owner/repo (default: auto-detect from CWD git remote)")
     ap.add_argument("--out", default=issue.ISSUE_ROOT,
-                    help="store root (default: <repo>/tmp/issues)")
+                    help="store root (default: <project>/.tea/issues)")
     args = ap.parse_args()
 
     filtered = bool(args.milestone or args.label or args.query)
@@ -229,9 +229,14 @@ def main():
 
     root = args.out
     # A first pull into a fresh checkout has to create the store; it says so,
-    # and the path is absolute, so it cannot be a stray cwd.
-    if issue.create_store(root):
-        sys.stderr.write("created store %s\n" % os.path.abspath(root))
+    # and the path is absolute, so it cannot be a stray cwd. With no project
+    # marker anywhere there is nowhere legitimate to put one — pulling into a
+    # guessed directory is what stranded issues inside the plugin.
+    try:
+        if issue.create_store(root):
+            sys.stderr.write("created store %s\n" % os.path.abspath(root))
+    except issue.StoreMissing as e:
+        _gitea.die(str(e))
 
     login = _gitea.require_login()