fix(bearings): support oversized fleet snapshots

[coreldh]

Intent

Fix PR 1964 so the large-fleet Bearings snapshot transport remains compatible with stock macOS Bash, its CI test inventory matches the new scale regression, and the existing open PR is validated and brought into the repository's no-mistakes publication custody. Do not force-push, merge, auto-merge, approve, or open a duplicate PR. The unrelated remote orphan-reap timeout was tested at origin/main and this head and also fails on PR 1965, so it is pre-existing or environment-dependent unless the pipeline establishes otherwise.

What Changed

• Stream fleet and Bearings snapshot JSON between jq stages instead of passing large payloads through command arguments.
• Preserve snapshot, secondmate-summary, and Bearings projections for inventories larger than the platform argument limit.
• Add an oversized-inventory regression fixture and update CI’s snapshot test inventory to 16 checks.

Risk Assessment

✅ Low: The diff consistently replaces large JSON argv transport with stdin streaming, retains projection semantics, and adds a macOS-scale regression plus matching CI inventory count.

Testing

Ran the focused fleet/Bearings suite on stock macOS Bash 3.2.57, then replayed the large-fleet path above ARG_MAX and captured the public Bearings JSON showing the in-flight task and all 320 queued gates; the CI inventory check matches the new 16-test expectation. This is a CLI-only change, so the transcript is the reviewer-visible product evidence. No worktree files were created or changed by testing.

Evidence: Large-fleet Bearings CLI output

BEARINGS_E2E= {"schema":"fm-bearings.v1","in_flight_ids":["argv-scale-live"],"queued_gate_count":320,"gate_ids":["argv-scale-0","argv-scale-319"]}

$ /bin/bash large-fleet-e2e.sh
BEARINGS_E2E=
{"schema":"fm-bearings.v1","in_flight_ids":["argv-scale-live"],"queued_gate_count":320,"gate_ids":["argv-scale-0","argv-scale-319"]}
ok - platform-derived oversized backlog and task inventory bypasses argv

Evidence: CI inventory check

CI snapshot inventory: expected=16 observed=16

$ snapshot_output=$(/bin/bash tests/fm-fleet-snapshot-view.test.sh); snapshot_count=$(printf ... | grep -c "^ok - "); test "$snapshot_count" -eq 16
CI snapshot inventory: expected=16 observed=16

Pipeline

Updates from git push no-mistakes

✅ **intent** - passed

✅ No issues found.

✅ **Rebase** - passed

✅ No issues found.

✅ **Review** - passed

✅ No issues found.

✅ **Test** - passed

✅ No issues found.

• /bin/bash tests/fm-fleet-snapshot-view.test.sh
• Evidence-only end-to-end replay of the oversized-inventory fixture under /bin/bash
• CI-equivalent snapshot inventory assertion: /bin/bash tests/fm-fleet-snapshot-view.test.sh with observed ok - inventory checked against 16

✅ **Document** - passed

✅ No issues found.

✅ **Lint** - passed

✅ No issues found.

✅ **Push** - passed

✅ No issues found.