feat(release-controller): add ignored_proposals to release-index.yaml

[pietrodimarco-dfinity]

Motivation

The reconciler rebuilds its in-memory ReconcilerState on every cycle from the public dashboard (/proposals?limit=50&include_topic=TOPIC_IC_OS_VERSION_ELECTION) and the governance canister (dre proposals filter -t ic-os-version-election), and treats every matching election proposal as "already submitted" regardless of status. A rejected or failed proposal therefore prevents the reconciler from ever submitting a fresh one for the same version — with no operator escape hatch.

Concretely, NNS election proposal 141776 (a rejected GuestOS election proposal) is currently blocking resubmission for its version. This PR adds the lever to unblock that and any similar future incident.

Design

Configuration-driven, not flag-driven:

• New top-level field on release-index.yaml: ignored_proposals: List[int].
• The reconciler reads index.root.ignored_proposals on every cycle from the freshly-loaded index and drops any matching proposal from the dashboard + governance lookups before they reach ReconcilerState.
• Edits to release-index.yaml on dfinity/dre@main are picked up by the running controller on the next cycle — no redeploy, no k8s PR, no image bump needed.
• Configuration lives versioned alongside the releases it pertains to.

This replaces an earlier iteration of this same PR that wired the same logic to a --ignore-proposal-id CLI flag (commit 72eaae5c); see the follow-up commit 09d9b76c for the pivot.

Changes

• release-index-schema.json: add the optional top-level ignored_proposals array (integer[]).
• release-controller/release_index.py: add ignored_proposals: List[int] = [] to the ReleaseIndex pydantic model (manual edit, mirroring the generator output — this file is already hand-tweaked).
• release-controller/reconciler.py: drop the --ignore-proposal-id argparse flag and the Reconciler.ignore_proposal_ids constructor parameter. _filtered_proposals_retriever is now a static method taking the ignore set explicitly, and reconcile() pulls it from index.root.ignored_proposals before invoking the wrappers. Every dropped proposal still emits a warning log identifying the source, OS kind, proposal id, and version.
• release-index.yaml: pin ignored_proposals: [141776] to force resubmission for the version that the rejected GuestOS proposal 141776 was blocking.
• release-controller/README.md: rewrite the operator runbook to point at the release-index.yaml workflow; drop the stale --skip-preloading-state dev-mode docs (the flag was never wired into main's argparse anyway).
• release-controller/tests/test_reconciler_integration.py: two unit-ish tests for the static filter wrapper (with / without ignore IDs), plus an end-to-end test asserting that an entry in release-index.yaml's ignored_proposals propagates through the loader into a fresh proposal submission via the dryrun DRECli.

Caveats

• The IC governance canister still independently refuses to re-elect a version that is already blessed. This flag only helps when the prior proposal did not result in a blessing (typically REJECTED or FAILED).
• The flag is non-persistent. Once the reconciler has run one cycle with 141776 ignored and submitted the replacement proposal, the entry should be removed from release-index.yaml so it does not silently swallow future state for that id.

Companion change

• dfinity-ops/k8s#2442 — closed as obsolete; the new design doesn't need a k8s change.

Test plan

• bazel test //release-controller:integration_tests --test_filter='test_reconciler_filtered_proposals|test_reconciler_picks_up' — all 5 tests pass (51.5 s).
• release-index.yaml validates against the updated release-index-schema.json (jsonschema).
• mypy clean on touched files.
• Once merged: confirm the running release-controller logs Ignoring dashboard guestos election proposal 141776 for version … on the next reconcile cycle, then submits a fresh GuestOS election proposal for the underlying version.
• Follow-up PR to remove the 141776 entry from release-index.yaml once the replacement proposal has been submitted.