fix(tools/git): detect-platform died silently outside a repo, taking every wrapper with it

detect_platform() and get_repo_info() both already contained the correct error path:

    remote_url=$(git remote get-url origin 2>/dev/null)
    if [[ -z "$remote_url" ]]; then
        echo "error: not a git repository or no origin remote" >&2
        return 1
    fi

but that message was UNREACHABLE. Every wrapper in this directory runs `set -e`, and
outside a git repo the assignment itself returns git's 128, terminating the caller
before the -z check. The diagnostic was written and could never print.

Observed cost: `pr-review.sh -n N -r owner/repo -H host -a comment -c "..."` invoked
from a non-repo cwd exits 128 with NO stdout and NO stderr -- including when -r and -H
are supplied, the flags whose help text says "skips git-remote inference". The inference
runs first regardless. Two reviewer seats hit this tonight and correctly reported
`blocked` with no diagnostic available to report; one of them lost a full review.

Reproduced:
    cd /tmp && pr-review.sh -n 1086 -r mosaicstack/stack -H git.mosaicstack.dev \
        -a comment -c "x"          -> rc=128, 0 bytes of output
    same command from inside a repo -> rc=1, "Error: Comment required"

`|| true` matches the idiom already used at the other two call sites in this same file
(one `|| return 1`, one `|| true`), so the file was internally inconsistent: two guarded
sites, two unguarded.

test-detect-platform-outside-repo.sh asserts the MESSAGE, not merely a non-zero rc --
"rc != 0" passes on the broken build too, since 128 is also non-zero. RED on main
(128:no for both functions), GREEN here (1:yes), with an in-repo control proving the
functions still resolve normally. Enumerated on test:framework-shell.

Found-by: be-coder-08, rev0 (both reported `blocked` per Gate 8 rather than working around it)

packages/mosaic/framework/tools/git/detect-platform.sh

@@ -5,7 +5,10 @@
 
 detect_platform() {
     local remote_url
-    remote_url=$(git remote get-url origin 2>/dev/null)
+    # `|| true` is load-bearing under `set -e`: outside a git repo this returns 128 and
+    # kills the CALLER before the -z check below can run, so the error message that is
+    # already written here was unreachable. Same idiom as get_gitea_repo_args() below.
+    remote_url=$(git remote get-url origin 2>/dev/null) || true
 
     if [[ -z "$remote_url" ]]; then
         echo "error: not a git repository or no origin remote" >&2
@@ -39,7 +42,10 @@ detect_platform() {
 
 get_repo_info() {
     local remote_url
-    remote_url=$(git remote get-url origin 2>/dev/null)
+    # `|| true` is load-bearing under `set -e`: outside a git repo this returns 128 and
+    # kills the CALLER before the -z check below can run, so the error message that is
+    # already written here was unreachable. Same idiom as get_gitea_repo_args() below.
+    remote_url=$(git remote get-url origin 2>/dev/null) || true
 
     if [[ -z "$remote_url" ]]; then
         echo "error: not a git repository or no origin remote" >&2

packages/mosaic/framework/tools/git/test-detect-platform-outside-repo.sh

@@ -0,0 +1,45 @@
+#!/bin/bash
+# Regression: detect_platform / get_repo_info must FAIL LOUDLY outside a git repo,
+# not kill the caller silently.
+#
+# Both functions already contained the right error path:
+#     if [[ -z "$remote_url" ]]; then echo "error: not a git repository..." >&2; return 1; fi
+# but under `set -e` -- which every wrapper in this directory uses -- the preceding
+# assignment `remote_url=$(git remote get-url origin 2>/dev/null)` returns git's 128
+# outside a repo and terminates the CALLER first. The message was unreachable.
+#
+# Observed cost: pr-review.sh invoked from a non-repo cwd exits 128 with NO stdout and
+# NO stderr, even when -r/--repo and -H/--host are supplied -- the flags documented as
+# "skips git-remote inference". Two reviewer seats hit this and correctly reported
+# `blocked` with no diagnostic to report.
+#
+# The control that matters is the LOUD one: asserting "rc != 0" passes on the broken
+# build too, because 128 is also non-zero. The test must assert the MESSAGE.
+set -uo pipefail
+fail=0
+HERE="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+TMP="$(mktemp -d)"; trap 'rm -rf "$TMP"' EXIT
+
+run_outside() { # $1=function name -> "rc:sawmessage"
+    local fn="$1" out rc
+    out=$( cd "$TMP" && bash -c "set -e; source '$HERE/detect-platform.sh'; $fn" 2>&1 ); rc=$?
+    printf '%s:%s' "$rc" "$(grep -qi 'not a git repository' <<<"$out" && echo yes || echo no)"
+}
+check() { if [ "$2" = "$3" ]; then echo "  PASS  $1 ($2)"; else echo "  FAIL  $1: got $2, want $3"; fail=1; fi; }
+
+# $TMP is deliberately not a git repo, and must not be inside one.
+( cd "$TMP" && git rev-parse --git-dir >/dev/null 2>&1 ) && { echo "  SKIP  scratch dir is inside a repo"; exit 0; }
+
+echo "== outside a git repo: rc=1 AND the diagnostic is emitted =="
+check "detect_platform" "$(run_outside detect_platform)" "1:yes"
+check "get_repo_info"   "$(run_outside get_repo_info)"   "1:yes"
+
+echo "== inside a git repo the functions still work =="
+git init -q "$TMP/repo" 2>/dev/null
+git -C "$TMP/repo" remote add origin https://git.mosaicstack.dev/mosaicstack/stack.git 2>/dev/null
+out=$( cd "$TMP/repo" && bash -c "set -e; source '$HERE/detect-platform.sh'; detect_platform" 2>&1 ); rc=$?
+if [ "$rc" -eq 0 ] && grep -qi 'gitea' <<<"$out"; then echo "  PASS  detect_platform in-repo (rc=0, $out)"
+else echo "  FAIL  detect_platform in-repo: rc=$rc out=$out"; fail=1; fi
+
+[ "$fail" -eq 0 ] && echo "OK  detect-platform fails loudly outside a repo" || echo "FAILED"
+exit "$fail"

packages/mosaic/package.json

@@ -6,7 +6,7 @@
     "url": "https://git.mosaicstack.dev/mosaicstack/stack.git",
     "directory": "packages/mosaic"
   },
-  "description": "Mosaic agent framework — installation wizard and meta package",
+  "description": "Mosaic agent framework \u2014 installation wizard and meta package",
   "type": "module",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",
@@ -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 src/lease-broker/daemon_deadline_unittest.py && python3 src/lease-broker/normative_fragments_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/framework_skill_portability_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-review-gitea-comment.sh && bash framework/tools/git/test-pr-review-repo-host-override.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-pr-merge-queue-branch.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/woodpecker/test-terminal-green-contract.sh && bash framework/tools/_scripts/test-install-ordering-guard.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"
+    "test:framework-shell": "bash framework/tools/quality/scripts/check-test-enumeration.sh && bash framework/tools/quality/scripts/test-check-test-enumeration.sh && python3 src/lease-broker/daemon_deadline_unittest.py && python3 src/lease-broker/normative_fragments_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/framework_skill_portability_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-review-gitea-comment.sh && bash framework/tools/git/test-pr-review-repo-host-override.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-pr-merge-queue-branch.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-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/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"
   },
   "dependencies": {
     "@mosaicstack/brain": "workspace:*",