ci: drop CLICOLOR_FORCE=1 from tend-setup action

[prql-bot]

Summary

Remove CLICOLOR_FORCE=1 from .github/actions/tend-setup. This env var silently breaks the CI-polling pattern used by every tend-review session, causing 15–20 min hangs on each polling attempt.

The bug

CLICOLOR_FORCE=1 tells tools to emit ANSI colour codes even when their stdout is a pipe. gh respects this for --json output: the JSON gets prefixed with escape codes, so piping gh pr view --json statusCheckRollup | jq ... fails with jq: parse error: Invalid numeric literal at line 1, column 2 on every call.

That is exactly the polling pattern the bundled tend-ci-runner:running-in-ci skill documents:

pending() {
  gh pr view <num> --json statusCheckRollup \
    | jq --arg own "/runs/$GITHUB_RUN_ID/" '
      [.statusCheckRollup[] | select(...) | ...] | length'
}
for i in $(seq 1 15); do
  sleep 60
  [ "$(pending)" -gt 0 ] && continue
  ...

When pending() returns an empty string (stderr-only output), [ "" -gt 0 ] is an integer expression expected error, so the first branch never triggers; the grace check [ "$(pending)" -eq 0 ] likewise errors and hits continue. The loop runs to its hardcoded timeout without ever registering that CI turned green.

Session-log evidence — run 24686601620 (review of PR #5816) spent 46 minutes bouncing between two polling attempts:

[iter 8] pending=-1
[iter 9] pending=-1
...
[iter 20] pending=-1
CI still running after 20 minutes

Why this wasn't caught

Past review-runs entries misattributed the 15-min/25-min review wall-clock to "CI waiting for tests to finish" (tracking issue #5787 entries for 2026-04-19 and 2026-04-20). Re-reading the raw session logs confirms the same jq: parse error was present in reviews for PRs #5810, #5811, and #5813 — 5+ occurrences over three days, all structurally the same.

Why this is safe

• CARGO_TERM_COLOR=always (kept) already forces cargo to emit coloured output — that's what most of the tend sessions actually care about.
• Other tools like grep / ls will fall back to the unix-convention behaviour (colour when tty, plain when piped), which is what the rest of the repo's CI already does.
• tests.yaml and the language-binding test workflows still set CLICOLOR_FORCE=1 at their own workflow level — untouched. Only tend's bot sessions lose the forced colour.

After this lands

• The next tend-review run will use the standard gh pr view --json ... | jq polling loop and actually see pending=0 when checks settle, exiting within the real CI duration instead of padding to the full 15-min cap.
• Follow-up: the tracking issue's 2026-04-19 / 2026-04-20 "15-min polling" findings can be marked resolved once the next review of a bot PR reports sub-5-min wall clock on CI-green.

Test plan

• Merge and observe the next tend-review run triggered by a subsequent bot PR; verify the review job exits within ~2 min of CI settling rather than hitting the 15-min timeout.
• Spot-check the session log from that run — confirm no jq: parse error: Invalid numeric literal in the pending() tool output.