docs: CI carry in CONTRIBUTING, recommended-harness and the pregate usage line (ship docs audit)

Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>

CONTRIBUTING.md

@@ -191,7 +191,8 @@ the new defaults.
 | Run one free test file while repairing | `bun test <file>` | Free, seconds | Never bare `bun test` for the suite |
 | Run full free acceptance before publishing | `bun run test` | Free, a few minutes | Bun 1.4.2 |
 | Run the full free suite from a small machine | `bun run test:ubicloud` | Free suite on a billed 16-vCPU VM, about 5 minutes | `UBICLOUD_API_KEY`, `UBI_OWNER` |
-| Clear pregate's test tier on a machine under 8 cores ([remote gate](docs/pregate.md#remote-gate)) | `gstack-pregate --stage tests --remote --spend-cap 2 --timeout 2700 --allow-repo-commands` (same command keyed or keyless) | Keyed: one billed 16-vCPU VM, about 7 minutes and $0.06 for the whole free tier, worst case $0.38; keyless: free, local parallel shards, practical for small selections only (98 files took 103 s on 4 cores) | Keyed: `UBICLOUD_API_KEY`, `UBI_OWNER`; keyless: nothing |
+| Clear pregate's test tier on a machine under 8 cores from CI, the default on gstack ([CI carry](docs/pregate.md#ci-carry)) | push, `gstack-ci-carry wait --base main`, then `gstack-pregate --allow-repo-commands` (a branch behind main first runs `gh workflow run free-tests.yml --ref <branch>`) | Free; reuses the green Free Tests run at your pushed tree | Pushed branch, `gh` |
+| Clear pregate's test tier on a machine under 8 cores when no CI run covers your tree ([remote gate](docs/pregate.md#remote-gate), opt-in) | `gstack-pregate --stage tests --remote --spend-cap 2 --timeout 2700 --allow-repo-commands` (same command keyed or keyless) | Keyed: one billed 16-vCPU VM, about 7 minutes and $0.06 for the whole free tier, worst case $0.38; keyless: free, local parallel shards, practical for small selections only (98 files took 103 s on 4 cores) | Keyed: `UBICLOUD_API_KEY`, `UBI_OWNER`; keyless: nothing |
 | Run the curated Windows-safe subset | `bun run test:windows` (CI: six `windows-latest` jobs, nightly on main; PRs run the shorter `windows-smoke` check) | Free | Windows, Git Bash |
 | Refresh the Windows duration seed | `gh workflow run windows-free-tests.yml --ref <branch> -f record_durations=true`, then commit the `free-test-durations-windows` artifact | Free CI runners | Pushed branch, `gh` with workflow rights |
 | Run a native Windows qualification campaign | `gh workflow run native-qualification.yml --ref <branch> -f mode=<mode>` ([modes](docs/TESTING_INTERNALS.md#windows-free-lane)) | Free CI runners | Pushed branch, `gh` with workflow rights |

docs/pregate.md

@@ -174,7 +174,7 @@ The list lives in its own file, not in `pregate.json`, because older pregate rea
 
 ```
 gstack-pregate [--stage preflight|tests|all] [--only <check,..>] [--allow-repo-commands] [--policy-from base|head]
-               [--timeout <s>] [--stall-timeout <s>] [--remote --spend-cap <usd>] [--run <id>] [--from-run <id|url>] [--explain] [--json]
+               [--timeout <s>] [--stall-timeout <s>] [--remote --spend-cap <usd>] [--run <id>] [--from-run <id|url>] [--no-ci-carry] [--explain] [--json]
 gstack-pregate verify | clear --remote <workflow.yml/job> --run-url <url> | lanes | validate | init
 ```
 

docs/recommended-harness.md

@@ -139,7 +139,9 @@ harness-generic; only the thread and the PR tool are Capy.
    default branch.
 4. **Run `/ship` unattended** with the `GSTACK_LAUNCH` assignments
    exported: it runs the pregate (on a machine under 8 cores the test tier
-   needs `gstack-pregate --stage tests --remote`, about $0.06 on a Ubicloud VM
+   clears from a verified CI run at the pushed tree when the base declares
+   `remote_gate_runs` ([CI carry](pregate.md#ci-carry)); otherwise it needs
+   `gstack-pregate --stage tests --remote`, about $0.06 on a Ubicloud VM
    or free locally for small selections), both reviews, the gate-integrity
    list, the docs audit, and writes the ship receipt into the PR body
    (`gstack-ship-receipt write --pr <n>`). With `queue_mode: