[fas89]

Documents forge-cli #813: fluid validate and fluid plan warn about a contract.id or builds[].id that the build phase refuses (1orders, or more than 128 characters). Plain validate passes, --strict fails, and plan still writes the plan.

• docs/cli/apply.md, "Build ids": the sentence that said validate and plan simply pass such an id now says they warn about it. The hint in the example output now reads "only warn about it", as #813 prints it.
• docs/cli/validate.md: a new section, "An id the build phase refuses", with the real output, the exit codes, --format json, and where the check runs (the contract file and a bundle's resolved contract, not workspace mode).
• docs/cli/plan.md: a Notes bullet. Plan prints the same warning and still writes the plan, whatever --mode says.
• docs/upgrading.md: an entry under "On forge-cli main since 0.26.0 (not yet released)", after the #803 and #808 ones.

Draft until #813 merges, because the text says "on main". Checked against #813's head a6758b80: the warning text, the hint and the exit codes come from running that tree. Local checks: check_cli_docs.py --markers-only, npm run docs:build and scripts/check-dist-links.mjs.

Update: #813 merged as 8c8116ed. I compared a6758b80 with the squash commit. Only #808's --build-id gate in apply.py and other PRs' CHANGELOG entries differ. The warning text, the apply hint and the CHANGELOG entry quoted here are unchanged, so the docs need no edit and the PR is ready for review.