docs: changelog for v2.8.0 and curated command docs for 33 new operations

[spark2ignite]

Prepares the v2.8.0 (minor) release by clearing both pre-tag gates in release.yml:

• CHANGELOG.md entry for v2.8.0 (--search, per-command flag help, help without credentials, AUTHENTICATION_REQUIRED login failures, dci status expiry). check-changelog.sh --gate v2.8.0 passes.
• Curated command-docs/ for the 33 GA operations the prod spec gained (roles, service accounts and tokens, signup, shared payers, commitment policies, widgets, CloudFlow trigger/stop, and others). commanddocs coverage -strict reports 243/243; prettier and TestCommandDocs pass.

Supersedes the stale draft-stub drift PRs (#180, #182, #185). Examples were written from the spec, not run against live responses.

After merge: git tag v2.8.0 && git push origin v2.8.0.

🤖 Generated with Claude Code

[claude]

LGTM — docs-only change (CHANGELOG entry plus 33 new command-docs/.yaml files), no Go source or tests touched. Checked: no real-looking customer/account/resource IDs in the new files (only placeholders like and generic example values); every command referenced in each new file's related: list resolves to an existing command-docs/.yaml; YAML structure (command/arguments/examples/notes/related) matches the established schema. Lines over the 120-char printWidth exist in several new files, but the same pattern is widespread across untouched pre-existing command-docs files, so it isn't a regression introduced by this diff. The CHANGELOG's v2.8.0 features (--search, scoped flag help, AUTHENTICATION_REQUIRED, dci status expiry) are already implemented in prior commits on this branch (6158e1d, 4230197, 0ec2a1e, 8b2534e) — this PR only adds the changelog entry and docs for them.

Extended reasoning...

Diff touches only CHANGELOG.md and 33 new command-docs/*.yaml files describing already-merged CLI features and pre-existing-but-undocumented API operations; no Go source, auth, or security-sensitive code is touched. Verified no real-looking IDs leaked into the new docs, all related-command cross-references resolve, and the apparent prettier line-width concern is actually a pre-existing repo-wide pattern rather than something new. No open reviewer objections in the timeline, and the change is additive and mechanical with no ambiguity.