fix: apply the review items for #744 at merge

Classify OpenSSL and LibreSSL's SSL_connect errors as unreachable again (`_` is a
word character, so \bssl\b missed them and the user read the temp directory as the
reason), point a cases-folder refusal at Clone Repo instead of Create New, and move
the mechanism and history out of CLAUDE.md into architecture-invariants.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/architecture-invariants.md

@@ -473,6 +473,8 @@ Tests: `test/file-preview-markdown.test.ts` (jsdom-in-vm, pins every rule above)
 - ⚠️ **The URL is a code-execution surface, which is why it is parsed rather than forwarded.** `ext::sh -c <cmd>` makes git run an arbitrary command as its transport, and ANY `<name>::<payload>` dispatches to a `git-remote-<name>` helper, so every `::` form is refused outright. A repository starting with `-` is read by git as a flag; that is rejected AND every spawn puts `--` before the operands, because either defence alone is one edit away from being a hole. Spawns are argv arrays, never a shell (unlike `remote-hosts.ts`, which does build a shell line and must `shellescape`). The Zod schema deliberately only length-bounds `repository` — a weaker regex duplicate of `parseGitRepositoryUrl` would be the copy that drifts.
 - ⚠️ **Non-interactive or it hangs the request.** The clone is synchronous by design (no job store, no polling, no cancellation surface), so an invisible credential prompt would pin an open HTTP request until the timeout. `gitNonInteractiveEnv()` closes all four prompt paths at once: `GIT_TERMINAL_PROMPT=0`, empty `GIT_ASKPASS`/`SSH_ASKPASS` + `SSH_ASKPASS_REQUIRE=never` + empty `DISPLAY`, `GCM_INTERACTIVE=never`, and `ssh -oBatchMode=yes`. `HOME`/`PATH` are inherited on purpose — a user whose own agent or credential helper already works keeps working (so a private repo may well clone; Codeman just never collects or stores credentials, and refuses a `user:password@` URL). ⚠️ In multi-user mode a NON-ADMIN's clone and preflight run with `git -c credential.helper=` (`cloneWithoutCredentialHelpers`), because the helpers belong to the one server account every user shares; admins and single-user mode keep them. The Docker server image relies on exactly this: when built with the opt-in `CODEMAN_INSTALL_GH`/`CODEMAN_INSTALL_AZ` args it configures `gh` (github.com) and an `az`-backed helper (`docker/git-credential-azure-cli`, Azure DevOps) in its SYSTEM gitconfig, both silent until the user signs the CLI in, so a private clone there still fails fast rather than prompting.
 - ⚠️ **Bounded in time, output and concurrency.** Timeout → SIGTERM → SIGKILL, signalled to the whole process GROUP (`detached: true`, negative pid) because `git clone` fans out into `git-remote-https`/`index-pack` children that a polite signal to the parent leaves running. stderr is kept as a bounded, credential-redacted, control-stripped TAIL; `ls-remote` stdout is capped and refs are capped at 500 each. A small global pool (default 2, `CODEMAN_MAX_GIT_OPERATIONS`) caps concurrent git network ops, same reasoning as `document-conversion-limiter.ts`.
+- ⚠️ **A direct clone's cleanup has a premise.** One direct (`intoEmptyDir`) clone per folder runs at a time, and a failed one empties the folder only when git actually ran (`GitRun.started`: a full queue or a slot wait that timed out wrote nothing) and did not refuse the folder. That refusal is read from git's own `already exists and is not an empty directory` text, tested directly and never through the classifier's code: the message quotes the path, and a folder named `openssl` once classified as unreachable. A folder whose mount stopped answering is left alone too (`probePathKind()`), so no libuv worker is held on it.
+- ⚠️ **No clone at or inside a Docker case workspace, with or without a `path`.** Git would run the new repository's hooks and filters on the host. Refused `400` on both branches.
 - **Repository contents beat scaffolding.** An existing `CLAUDE.md` is kept (a generated one is written only when absent) and hooks are MERGED into whatever `.claude/settings.local.json` the repo shipped. A repo that ships its own `.claude/settings*.json` is reported back as a warning, because repo-supplied hooks run on the user's machine as soon as a session starts there.
 - **Failure leaves nothing behind.** The destination is removed only when it did not exist before the attempt, and a pre-existing directory is refused rather than cloned into, so a failed clone never squats on a case name and never touches an existing tree.
 - ⚠️ **Error detail comes from the LAST diagnostic line, not the first.** `git clone` opens with `Cloning into '<dest>'…`, so a first-line pick reported the destination path as the reason a bad branch failed (observed against a real remote). `NOT_FOUND` wording must also say "or private": GitHub answers "Repository not found" for a private repo and a typo alike when unauthenticated.