fix(framework/tools): wrapper body-safety + login-resolution hardening (#559, #560)

#559 — Markdown body safety / eval removal:
- Add test-issue-create-body-safety.sh: feeds a hostile Markdown body
  ($(...), backticks, quotes, $vars, pipes) through issue-create.sh and
  asserts no command substitution runs and the body reaches tea verbatim.
- Convert issue-comment.sh from unquoted $(get_gitea_repo_args) word-splitting
  to an argv array with an explicit loud login-resolution error.
- Confirmed: zero eval usages remain across tools/git/*.sh; the other
  body-carrying wrappers (issue-create, pr-create, issue-edit, issue-assign)
  already use argv arrays.

#560 — host-derived Gitea login + loud failure:
- detect-platform.sh: add print_gitea_login_diagnostic and emit it on the
  get_gitea_login_for_host failure path (stderr only) — names the unresolved
  host, lists available tea logins, and gives the GITEA_LOGIN override +
  tea-login-add fix. Replaces the previous silent failure.
- Extend test-gitea-login-resolution.sh: assert the diagnostic fires and lists
  logins, login is derived from origin host for both mosaicstack and usc (scoped
  second tea mock), and a valid GITEA_LOGIN override is honored.

Also gitignore the .mosaic-test-work/ shell-harness scratch dir.
Scope: wrapper surface only. All wrapper test harnesses pass locally.

docs/scratchpads/559-560-wrapper-eval-login-20260620.md

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+# Wrapper hardening fold-in: #559 (eval removal) + #560 (host-derived login)
+
+**Branch:** `fix/wrapper-hardening-tls-credpath-cicwait` (PR #551)
+**Worker:** coderlite0 (Sonnet lane) · coordinated by mos-claude
+**Date:** 2026-06-20
+**Scope:** `packages/mosaic/framework/tools/git/*.sh` only
+
+## What the issues asked for vs. what was already landed
+
+Both issues were largely satisfied by prior merged work; this fold-in closes the
+remaining gaps (regression tests + a loud diagnostic + one residual word-split site)
+rather than re-implementing finished functionality.
+
+### #559 — remove `eval` from issue-create.sh (and siblings)
+
+- `eval`-based command construction was already removed across the wrapper surface
+  (landed in #549). A full scan of `tools/git/*.sh` finds **zero** `eval` usages.
+- `issue-create.sh`, `pr-create.sh`, `issue-edit.sh`, `issue-assign.sh` already build
+  their `tea`/`gh` invocations as argv arrays (`CMD=(...)`, `"${CMD[@]}"`), so Markdown
+  bodies pass through verbatim.
+- **Residual found & fixed:** `issue-comment.sh` still used unquoted
+  `$(get_gitea_repo_args)` word-splitting (the comment body itself was already safely
+  quoted, so no injection bug — but it was the inconsistent, fragile pattern #559 targets,
+  and it failed silently when no login resolved). Converted to an argv array with an
+  explicit, loud login-resolution error.
+- **Added regression test:** `test-issue-create-body-safety.sh` — feeds a hostile
+  Markdown body (`$(touch SENTINEL)`, backticks, single/double quotes, `$HOME`/`${PATH}`,
+  pipes/`&&`/`;`) through `issue-create.sh` and asserts (1) no command substitution
+  executes (sentinel file never created) and (2) the `--description` `tea` receives is
+  byte-for-byte the original body.
+
+### #560 — auto-detect Gitea `--login` from repo origin host
+
+- Centralized host→login resolution already exists in `detect-platform.sh`
+  (`get_gitea_login_for_host` → `find_tea_login_for_host`, matching `urlparse(url).hostname`).
+  Every wrapper routes through it (or `get_gitea_login` / `get_gitea_login_for_repo_override`);
+  **no wrapper hardcodes `${GITEA_LOGIN:-mosaicstack}`**. Explicit `GITEA_LOGIN` wins only
+  when it matches the host (`tea_login_matches_host`), so stale overrides are rejected.
+- **Gap fixed — silent failure → loud diagnostic:** the failure path of
+  `get_gitea_login_for_host` returned non-zero with no message. Added
+  `print_gitea_login_diagnostic`, emitted to **stderr** on resolution failure: names the
+  unresolved host, lists available tea logins (name + host), and gives the `GITEA_LOGIN`
+  override + `tea login add` fix. Stderr-only, so it never contaminates stdout (the
+  resolved login name) or the log-grep assertions in the existing harnesses. Callers with
+  an API fallback (pr-merge, issue-close, pr-create, issue-create) still follow with their
+  own "using API fallback" line, giving a clear "no login → fallback" trail.
+- **Extended test:** `test-gitea-login-resolution.sh` now also asserts (a) the loud
+  diagnostic fires and lists available logins for an unresolved host, (b) login is derived
+  from origin host for **both** instances (mosaicstack + usc) via a scoped second `tea`
+  mock, and (c) a valid `GITEA_LOGIN` override is honored. The scoped mock keeps the
+  existing API-fallback assertions (which require mosaicstack to have _no_ tea login) valid.
+
+## Files changed (wrapper surface only)
+
+- `detect-platform.sh` — add `print_gitea_login_diagnostic`; call it on the
+  `get_gitea_login_for_host` failure path.
+- `issue-comment.sh` — argv array + loud login-resolution error (was unquoted
+  `$(get_gitea_repo_args)`).
+- `test-issue-create-body-safety.sh` — **new** (#559 regression).
+- `test-gitea-login-resolution.sh` — extended (#560 diagnostic + both-host + override).
+
+## Verification
+
+All wrapper harnesses pass locally:
+
+- `test-issue-create-body-safety.sh` — PASS
+- `test-gitea-login-resolution.sh` — PASS
+- `test-pr-merge-gitea-empty-uid.sh` — PASS
+- `test-pr-metadata-gitea.sh` — PASS
+- `test-lane-brief-pr-linkage.sh` — PASS
+
+## Open items flagged to mos-claude (orchestrator decisions)
+
+1. **CHANGELOG absent.** The task said "update CHANGELOG (append-only), keep the existing
+   #550/#551 entry." No CHANGELOG file exists anywhere in the repo, and #550/#551 are not
+   recorded in one. **ASSUMPTION:** documenting #559/#560 in this scratchpad + the PR
+   description (`Closes #559 Closes #560`) follows the repo's actual convention
+   (`docs/scratchpads/`). Did not invent a new CHANGELOG structure.
+2. **`docs/TASKS.md` is orchestrator single-writer.** It carries a "Workers read but never
+   modify" banner. As a worker I did **not** edit it; task tracking is via the linked Gitea
+   issues #559/#560 + this scratchpad. Orchestrator may add a rollup row if desired.
+3. **Wrapper `test-*.sh` are not CI-wired.** `.woodpecker/ci.yml` runs `pnpm
+typecheck/lint/format:check/test` (`turbo run test`); the framework dir has no
+   `package.json`, so these shell harnesses run **locally/manually only** — they do not gate
+   the PR in Woodpecker. **ASSUMPTION:** out of scope to wire a shell-test step into CI in
+   this PR (would broaden the diff beyond the wrapper surface). Flagging for a follow-up if
+   the fleet wants these gated.