test(ios): close T-iOS-32's end-to-end half — real worktree lifecycle against a real server

T-iOS-32's acceptance is "builder 测试 + 端到端一次". The builder half was green,
but grep for projects/worktree across the whole test tree returned nothing — no
test had ever created or removed a real git worktree against a real server.

Six tests on a throwaway git fixture: create/remove/prune verified against both
the filesystem and git's own `worktree list --porcelain` + .git/worktrees/, and
asserting the values the SERVER derives rather than echoing our input (branch
feature/e2e-worktree becomes directory feature-e2e-worktree; the raw branch name
must never appear in the path). Includes a differential leg for the guarded-route
rule — the same request without Origin is 403 with zero side effects, and with it
is 200 — which needs raw URLSession, since APIClient structurally cannot emit an
Origin-less guarded request.

GET /sessions gets its own HOME-isolated server: history.ts reads
os.homedir()/.claude/projects, so against the shared harness the assertions would
land on the developer's real Claude history, and in CI the directory is absent so
it degrades to [] and proves nothing.

Integration tests 26 -> 32, independently re-run.

docs/PROGRESS_LOG.md

@@ -38,7 +38,7 @@
   |---|---|---|
   | 包测试 | 310 | **452** |
   | App 测试 | 296(1 失败) | **550**(iPhone + iPad 各一遍,**0 known issue**) |
-  | 集成测试 | 10 | **26** |
+  | 集成测试 | 10 | **32** |
   | Android 测试 | 687 | **691** |
   | ClientTLS 覆盖率 | 55.76%(**不在门内**) | **89.49%**(已入门) |
   | 覆盖率门 | 4 个包 | **5 个包全过**(最低余量 +9.49pp) |