fix(git-tools): WP5a rework — authoritative curl status, string-validated base, CI enumeration (E4)

T51P2WP5AR B1-B3 + I1 on the default-base fallback:

B1: test-pr-create-fallback-default-base.sh is now enumerated on the
canonical S1 surface (packages/mosaic package.json test:framework-shell,
git-tools cluster). Enumeration guard: population 67, enumerated 53,
excluded 15 — green; the meta-test passes 14/14. PR pipeline 2623's
sanitization failure clears on the next run.

B2: gitea_default_branch fetches and parses as separate steps. The old
`curl | python` pipeline reported only python's status, so an HTTP
failure that still emitted parseable JSON masqueraded as success and
POSTed. curl's exit status is now authoritative (rc nonzero -> failed
resolution, loud -B remedy, no POST). Fixture: valid JSON + curl rc 22.

B3: default_branch is valid only as a nonblank JSON string. null (which
printed as the literal "None"), numbers, and whitespace-only strings were
all POSTed as bases. The python step now type- and blank-checks; null /
numeric / blank fixtures each produce rc 1, loud -B remedy, no POST.

I1: --help now says the default base is the forge repository's default
branch (was main/master, the removed behavior).

Suite: 29 asserts (16 prior + 4 B2 + 9 B3), green x2. Sweep 32/33;
test-issue-close-fail-closed.sh fails identically at baseline origin/next
(pre-existing, untouched).

packages/mosaic/framework/tools/git/pr-create.sh

@@ -23,16 +23,33 @@ gitea_default_branch() {
     # Forge default branch for the current repo (T51-P2 WP5a / spec E4): the
     # API fallback must not guess a base. Empty output or any lookup failure
     # returns nonzero so the caller fails loud instead of mistargeting a PR.
-    local host repo token url branch
+    local host repo token url body branch
     host=$(get_remote_host) || return 1
     repo=$(get_repo_info) || return 1
     token=$(get_gitea_token "$host") || return 1
     url="https://${host}/api/v1/repos/${repo}"
-    branch=$(curl -fsS \
+    # Fetch and parse as separate steps (T51P2WP5AR B2): a piped
+    # `curl | python` reports only python's status, so an HTTP failure that
+    # still emits parseable JSON would masquerade as success. curl's own
+    # exit status is authoritative here.
+    if ! body=$(curl -fsS \
         -H "User-Agent: curl/8" \
         -H "Authorization: token ${token}" \
-        "$url" \
-        | python3 -c 'import json,sys; print(json.load(sys.stdin).get("default_branch",""))' 2>/dev/null) || return 1
+        "$url" 2>/dev/null); then
+        return 1
+    fi
+    # A valid base is a NONBLANK JSON STRING (T51P2WP5AR B3): null, numbers,
+    # and whitespace-only values are failed resolution, never a POSTed base.
+    branch=$(printf '%s' "$body" | python3 -c '
+import json, sys
+try:
+    value = json.load(sys.stdin).get("default_branch")
+except Exception:
+    sys.exit(1)
+if not isinstance(value, str) or not value.strip():
+    sys.exit(1)
+print(value.strip())
+' 2>/dev/null) || return 1
     [[ -n "$branch" ]] || return 1
     printf '%s' "$branch"
 }
@@ -104,7 +121,7 @@ Create a pull request on the current repository (Gitea or GitHub).
 Options:
     -t, --title TITLE       PR title (required, or use --issue)
     -b, --body BODY         PR description/body
-    -B, --base BRANCH       Base branch to merge into (default: main/master)
+    -B, --base BRANCH       Base branch to merge into (default: the forge repository's default branch)
     -H, --head BRANCH       Head branch with changes (default: current branch)
     -l, --labels LABELS     Comma-separated labels
     -m, --milestone NAME    Milestone name

packages/mosaic/framework/tools/git/test-pr-create-fallback-default-base.sh

@@ -54,12 +54,17 @@ mode="\${CURL_STUB_GET_MODE:-ok}"
 printf '%s\n' "\$*" >> "$ROOT/curl-calls.log"
 url="\${!#}"
 if [[ "\$url" == */api/v1/repos/acme/widgets ]]; then
-    # repo GET (default-branch resolution)
-    if [[ "\$mode" != "ok" ]]; then
-        echo "curl stub: simulated repo lookup failure" >&2
-        exit 1
-    fi
-    printf '%s\n' '{"id":1,"default_branch":"next","full_name":"acme/widgets"}'
+    # repo GET (default-branch resolution). Modes cover the value shapes the
+    # resolver must accept or refuse (T51P2WP5AR B2/B3).
+    case "\$mode" in
+        ok)         printf '%s\n' '{"id":1,"default_branch":"next","full_name":"acme/widgets"}' ;;
+        fail)       echo "curl stub: simulated repo lookup failure" >&2; exit 1 ;;
+        fail-json)  printf '%s\n' '{"default_branch":"next"}'; exit 22 ;;
+        null)       printf '%s\n' '{"default_branch":null}' ;;
+        numeric)    printf '%s\n' '{"default_branch":7}' ;;
+        blank)      printf '%s\n' '{"default_branch":"   "}' ;;
+        *)          echo "curl stub: unknown GET mode \$mode" >&2; exit 1 ;;
+    esac
     exit 0
 fi
 if [[ "\$url" == */api/v1/repos/acme/widgets/pulls ]]; then
@@ -131,6 +136,39 @@ run_pr_create -t "fix thing"
 assert_rc "rc" 0 "$RC"
 assert_eq "base field is next, never main" "next" "$(json_field "$ROOT/payload.json" base)"
 
+echo "== (5) B2: HTTP failure with parseable JSON on stdout is a FAILED resolution =="
+: > "$ROOT/curl-calls.log"; rm -f "$ROOT/payload.json"
+RC=0
+OUT=$(cd "$ROOT/repo" && env -i \
+    PATH="$ROOT/stub:/usr/bin:/bin" \
+    HOME="$ROOT/home" \
+    GITEA_TOKEN=stub-token \
+    CURL_STUB_GET_MODE=fail-json \
+    bash "$TOOLS/pr-create.sh" -t "fix thing" 2>"$ROOT/err.txt")
+RC=$?
+ERR="$(cat "$ROOT/err.txt")"
+assert_rc "nonzero rc on HTTP failure despite valid JSON" 1 "$RC"
+assert_contains "loud error names -B" "$ERR" "could not resolve the forge default branch"
+assert_contains "error names the remedy" "$ERR" "pass -B <branch> explicitly"
+assert_eq "no POST issued" 0 "$(calls_matching '/pulls$')"
+
+echo "== (6) B3: null / numeric / blank default_branch are failed resolutions =="
+for bad in null numeric blank; do
+    : > "$ROOT/curl-calls.log"; rm -f "$ROOT/payload.json"
+    RC=0
+    OUT=$(cd "$ROOT/repo" && env -i \
+        PATH="$ROOT/stub:/usr/bin:/bin" \
+        HOME="$ROOT/home" \
+        GITEA_TOKEN=stub-token \
+        CURL_STUB_GET_MODE="$bad" \
+        bash "$TOOLS/pr-create.sh" -t "fix thing" 2>"$ROOT/err.txt")
+    RC=$?
+    ERR="$(cat "$ROOT/err.txt")"
+    assert_rc "B3 $bad: nonzero rc" 1 "$RC"
+    assert_contains "B3 $bad: loud error" "$ERR" "could not resolve the forge default branch"
+    assert_eq "B3 $bad: no POST issued" 0 "$(calls_matching '/pulls$')"
+done
+
 echo
 echo "pass=$PASS fail=$FAIL"
 if [ "$FAIL" -gt 0 ]; then

packages/mosaic/package.json

@@ -25,7 +25,7 @@
     "lint": "eslint src",
     "typecheck": "tsc --noEmit",
     "test": "vitest run --passWithNoTests && pnpm run test:framework-shell",
-    "test:framework-shell": "bash framework/tools/quality/scripts/check-test-enumeration.sh && bash framework/tools/quality/scripts/test-check-test-enumeration.sh && python3 framework/tools/quality/scripts/test-framework-drift-check.py && bash framework/tools/quality/scripts/test-framework-drift-doctor.sh && bash framework/systemd/user/test-fleet-units.sh && python3 src/lease-broker/daemon_deadline_unittest.py && python3 src/lease-broker/normative_fragments_unittest.py && python3 src/lease-broker/promotion_binding_unittest.py && python3 src/lease-broker/promotion_trigger_unittest.py && python3 src/lease-broker/receipt_challenge_unittest.py && python3 src/lease-broker/context_recovery_unittest.py && python3 src/lease-broker/recovery_runtime_unittest.py && python3 src/lease-broker/recovery_b1_adversarial_unittest.py && python3 src/lease-broker/receipt_observer_client_unittest.py && python3 src/lease-broker/invariant_r_unittest.py && python3 src/lease-broker/framework_skill_portability_unittest.py && python3 src/lease-broker/revoke_noop_unittest.py && python3 src/mutator-gate/runtime_tools_unittest.py && python3 src/mutator-gate/runtime_launch_guard_unittest.py && python3 src/mutator-gate/version_coupling_unittest.py && python3 framework/tools/lease-broker/check-runtime-launches.py --root ../.. && bash framework/tools/codex/test-pr-diff-context.sh && bash framework/tools/qa/test-deps-preflight.sh && bash framework/tools/git/test-pr-edit.sh && bash framework/tools/git/test-pr-review-gitea-comment.sh && bash framework/tools/git/test-pr-review-repo-host-override.sh && bash framework/tools/git/test-ci-queue-wait-no-status.sh && bash framework/tools/git/test-ci-queue-wait-branch-absent.sh && bash framework/tools/git/test-ci-queue-wait-tristate.sh && bash framework/tools/git/test-ci-queue-wait-github-checks.sh && bash framework/tools/git/test-ci-queue-wait-no-ci-expected.sh && bash framework/tools/git/test-pr-merge-queue-branch.sh && bash framework/tools/git/test-pr-merge-no-ci-expected.sh && bash framework/tools/git/test-pr-merge-fork-ci-status.sh && bash framework/tools/git/test-pr-merge-head-pin.sh && bash framework/tools/git/test-pr-merge-message-field.sh && bash framework/tools/git/test-git-credential-mosaic.sh && bash framework/tools/git/test-gitea-token-identity.sh && bash framework/tools/git/test-explain-diagnostic-status-neutral.sh && bash framework/tools/git/test-detect-platform-outside-repo.sh && bash framework/tools/woodpecker/test-terminal-green-contract.sh && bash framework/tools/_scripts/test-install-ordering-guard.sh && bash framework/tools/_scripts/test-mosaic-init-rce.sh && bash framework/tools/tmux/agent-send.test.sh && bash framework/tools/wake/test-wake-store-ack.sh && bash framework/tools/wake/test-wake-store-enqueue-race.sh && bash framework/tools/wake/test-wake-digest-hmac.sh && bash framework/tools/wake/test-wake-digest-quarantine.sh && bash framework/tools/wake/test-wake-detector.sh && bash framework/tools/wake/test-wake-fn-oracle.sh && bash framework/tools/wake/test-wake-reconcile.sh && bash framework/tools/wake/test-wake-beacon.sh && bash framework/tools/wake/test-wake-preimage.sh && bash framework/tools/wake/test-wake-install.sh && bash framework/tools/glpi/test-list-http-status.sh && bash framework/tools/orchestrator/test-board-roll.sh && bash framework/tools/woodpecker/test-ci-wait-exit-matrix.sh && bash framework/tools/_scripts/test-fleet-transport-check.sh && bash framework/tools/_scripts/test-brain-home-check.sh && bash framework/tools/fleet/test-agent-session-broker-preflight.sh"
+    "test:framework-shell": "bash framework/tools/quality/scripts/check-test-enumeration.sh && bash framework/tools/quality/scripts/test-check-test-enumeration.sh && python3 framework/tools/quality/scripts/test-framework-drift-check.py && bash framework/tools/quality/scripts/test-framework-drift-doctor.sh && bash framework/systemd/user/test-fleet-units.sh && python3 src/lease-broker/daemon_deadline_unittest.py && python3 src/lease-broker/normative_fragments_unittest.py && python3 src/lease-broker/promotion_binding_unittest.py && python3 src/lease-broker/promotion_trigger_unittest.py && python3 src/lease-broker/receipt_challenge_unittest.py && python3 src/lease-broker/context_recovery_unittest.py && python3 src/lease-broker/recovery_runtime_unittest.py && python3 src/lease-broker/recovery_b1_adversarial_unittest.py && python3 src/lease-broker/receipt_observer_client_unittest.py && python3 src/lease-broker/invariant_r_unittest.py && python3 src/lease-broker/framework_skill_portability_unittest.py && python3 src/lease-broker/revoke_noop_unittest.py && python3 src/mutator-gate/runtime_tools_unittest.py && python3 src/mutator-gate/runtime_launch_guard_unittest.py && python3 src/mutator-gate/version_coupling_unittest.py && python3 framework/tools/lease-broker/check-runtime-launches.py --root ../.. && bash framework/tools/codex/test-pr-diff-context.sh && bash framework/tools/qa/test-deps-preflight.sh && bash framework/tools/git/test-pr-edit.sh && bash framework/tools/git/test-pr-create-fallback-default-base.sh && bash framework/tools/git/test-pr-review-gitea-comment.sh && bash framework/tools/git/test-pr-review-repo-host-override.sh && bash framework/tools/git/test-ci-queue-wait-no-status.sh && bash framework/tools/git/test-ci-queue-wait-branch-absent.sh && bash framework/tools/git/test-ci-queue-wait-tristate.sh && bash framework/tools/git/test-ci-queue-wait-github-checks.sh && bash framework/tools/git/test-ci-queue-wait-no-ci-expected.sh && bash framework/tools/git/test-pr-merge-queue-branch.sh && bash framework/tools/git/test-pr-merge-no-ci-expected.sh && bash framework/tools/git/test-pr-merge-fork-ci-status.sh && bash framework/tools/git/test-pr-merge-head-pin.sh && bash framework/tools/git/test-pr-merge-message-field.sh && bash framework/tools/git/test-git-credential-mosaic.sh && bash framework/tools/git/test-gitea-token-identity.sh && bash framework/tools/git/test-explain-diagnostic-status-neutral.sh && bash framework/tools/git/test-detect-platform-outside-repo.sh && bash framework/tools/woodpecker/test-terminal-green-contract.sh && bash framework/tools/_scripts/test-install-ordering-guard.sh && bash framework/tools/_scripts/test-mosaic-init-rce.sh && bash framework/tools/tmux/agent-send.test.sh && bash framework/tools/wake/test-wake-store-ack.sh && bash framework/tools/wake/test-wake-store-enqueue-race.sh && bash framework/tools/wake/test-wake-digest-hmac.sh && bash framework/tools/wake/test-wake-digest-quarantine.sh && bash framework/tools/wake/test-wake-detector.sh && bash framework/tools/wake/test-wake-fn-oracle.sh && bash framework/tools/wake/test-wake-reconcile.sh && bash framework/tools/wake/test-wake-beacon.sh && bash framework/tools/wake/test-wake-preimage.sh && bash framework/tools/wake/test-wake-install.sh && bash framework/tools/glpi/test-list-http-status.sh && bash framework/tools/orchestrator/test-board-roll.sh && bash framework/tools/woodpecker/test-ci-wait-exit-matrix.sh && bash framework/tools/_scripts/test-fleet-transport-check.sh && bash framework/tools/_scripts/test-brain-home-check.sh && bash framework/tools/fleet/test-agent-session-broker-preflight.sh"
   },
   "dependencies": {
     "@mosaicstack/brain": "workspace:*",