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/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:*",