[architect] refactor: delete production-dead pkg/hub spoke alias layer and duplicate test copies

[kubestellar-hive]

Refactor

Cluster claimed: src/pkg/hub/spoke_deleted_aliases.go + the 7 pkg/hub test files that referenced its aliases (sso_test.go, heartbeat_activity_test.go deleted; hub_keys_test.go, image_tag_validation_test.go, small_gaps_coverage_test.go, sso_ed25519_coverage_test.go, terminal_key_per_hive_test.go retargeted) and VerifySSOTokenAcrossKeys in hub_pubkey_generations.go. Disjoint from #6292 (config/backends.conf), #6257 (pkg/dashboard/api.go), and #6309 (none of these files in its 218-file diff).

What this changes structurally and why

After the spoke extraction (#6068), pkg/hub/spoke_deleted_aliases.go kept ~21 pass-through aliases. deadcode ./cmd/hive at v5 tip shows 15 are unreachable from any binary — production callers (pkg/dashboard/session.go, api.go, etc.) already import pkg/hub/spoke directly. The dead aliases only kept hub-side test copies compiling, several via lossy JSON marshal/unmarshal round-trips between the duplicated hub/spoke struct types (silently dropping drifted fields instead of surfacing them).

• Delete 5 zero-reference aliases: CollectClusterHealth, OpenFDCount, FDSoftLimit, RolloutRestartSelf, UpgradeSelfToSHA
• Delete pkg/hub/sso_test.go + pkg/hub/heartbeat_activity_test.go — byte-identical duplicates of their pkg/hub/spoke twins (12 tests ran twice per CI shard)
• Retarget remaining alias calls in 5 mixed test files to spoke.*
• VerifySSOTokenAcrossKeys now calls spoke.VerifySSOToken directly
• Keep only the 6 live pass-throughs (QuotaExhaustedProcessCount/AgentReason, HashDashboardToken, SelfImageReleaseChannel, SelfDeploymentImage, MintSSOToken) with a comment pointing new code at pkg/hub/spoke

No behavior change.

Verification

• go build ./... — ok
• go test ./pkg/hub — ok, coverage 91.3% → 91.4%
• Pre-existing (unrelated) failure on this host: TestSpokeKeyResolutionAndRotation in pkg/hub/spoke fails identically at clean v5 tip because host env HIVE_SSO_PUBLIC_KEY leaks into it — non-hermetic test, beaded separately.

Fixes #6326

---

Filed by architect agent (ACMM L5 — hold-gated mode). Hold-gated: human review required.

— hive: agent=architect backend=copilot model=claude-opus-4-6

[kubestellar-prow]

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[clubanderson]

Hold-gate review: deletion is production-dead (verified), but the PR is red on errors it introduces. Not lifting hold yet.

Verified against origin/v5 = b65e1bb (this PR's merge-base, behind_by: 0, so the CI reds below are fresh, not the #6310/#6316 stale ones). Grep used git grep -n -w over the whole tree; test files inspected separately.

1. Per-symbol evidence (deleted aliases in src/pkg/hub/spoke_deleted_aliases.go)

Every production caller that spells hub.X for these names imports the spoke package under the alias name hub, so the identifier already resolves to spoke.X, not to this file:

• src/cmd/hive/hubwire.go:14: hub "github.com/hivecommons/hive/pkg/hub/spoke"
• src/pkg/dashboard/session.go:12: hub "github.com/hivecommons/hive/pkg/hub/spoke"
• src/pkg/dashboard/terminal_handoff.go:10: hub "github.com/hivecommons/hive/pkg/hub/spoke"

Deleted symbol	Non-test callers of the pkg/hub alias	Verdict
InferenceBudgetProvider (type alias)	none	dead
CollectClusterHealth	hubwire.go:899 only, via spoke-as-hub import	dead
OpenFDCount	hubwire.go:758 only, via spoke-as-hub import	dead
FDSoftLimit	hubwire.go:759 only, via spoke-as-hub import. heartbeat.go:210 is the struct FIELD FDSoftLimit uint64 \json:"fd_soft_limit"`` on the hub-side report type, which this PR does not touch, so the wire tag is unaffected	dead
AgentActivityFor	hubwire.go:638,1182 only, via spoke-as-hub import	dead in prod, LIVE in tests (see 3)
HeartbeatKickInterval	none	dead in prod, LIVE in tests (see 3)
spokeAgentSummaries (unexported)	none outside the alias file	dead
QuotaExhaustedAgentCount	none	dead in prod, LIVE in tests (see 3)
ProviderLimitHeartbeatFields	hubwire.go:699,1188 only, via spoke-as-hub import	dead in prod, LIVE in tests (see 3)
RolloutRestartSelf	hubwire.go:999,1136 only, via spoke-as-hub import; other hits are comments	dead
SwitchImageSelf	hubwire.go:402 only, via spoke-as-hub import	dead
UpgradeSelfToSHA	hubwire.go:1128 only, via spoke-as-hub import	dead
VerifySSOToken	hub_pubkey_generations.go:365 in-package, retargeted by this PR to spoke.VerifySSOToken	dead after retarget
TerminalSigningKey	dashboard/session.go:251, terminal_handoff.go:61,115, all via spoke-as-hub import	dead
MintTerminalAssertion	dashboard/session.go:262, via spoke-as-hub import	dead
VerifyTerminalAssertion	terminal_handoff.go:115, via spoke-as-hub import	dead

Non-Go surfaces: no config keys, openapi fields, or dashboard JS reference any of these names. The only non-Go hits are comments in src/proxy/server.js and src/docs/design/master-key-rotation.md saying the JS mirrors hub.TerminalSigningKey / hub.VerifyTerminalAssertion; those describe the spoke implementation and stay accurate. None of the deleted items is a struct field, so no JSON tag is removed.

2. Duplicate tests

diff of pkg/hub/sso_test.go vs pkg/hub/spoke/sso_test.go and of pkg/hub/heartbeat_activity_test.go vs pkg/hub/spoke/heartbeat_activity_test.go: the only differing line in each is package hub vs package spoke. Same 7 + 5 test functions, same assertions. True duplicates.

3. Blocking: the PR breaks the cmd/hive test package

The retarget missed src/cmd/hive/, which imports the real pkg/hub (not the spoke alias) and calls the deleted functions:

• src/cmd/hive/agent_activity_test.go:47,79,87,93,104,116: hub.AgentActivityFor
• src/cmd/hive/heartbeat_idle_cadence_test.go:18,23,28: hub.HeartbeatKickInterval
• src/cmd/hive/config_overrides_replay_test.go:169,190: hub.ProviderLimitHeartbeatFields
• src/cmd/hive/provider_budget_probe_test.go:247: hub.ProviderLimitHeartbeatFields
• src/cmd/hive/quota_exhausted_agents_test.go:23,31,34: hub.QuotaExhaustedAgentCount

Check-runs on 6427f1c: golangci-lint, test (rest 1/3), and build-and-test all fail with undefined: hub.AgentActivityFor / hub.ProviderLimitHeartbeatFields / hub.HeartbeatKickInterval (FAIL github.com/hivecommons/hive/cmd/hive [build failed]). The PR body's "go build ./... ok" is true because binaries compile; go vet / go test ./cmd/hive does not.

Also red: changelog-fragment-guard. changelog.d/changed-6326-dead-spoke-aliases.md must start with a - bullet; it currently starts with the emoji.

Needed to lift hold

1. Retarget the five src/cmd/hive/*_test.go call sites to spoke.* (and switch []hub.AgentSummary literals in those tests to []spoke.AgentSummary where the parameter type changes).
2. Prefix the changelog fragment with - .

Once that is pushed and lint/test are green I will re-verify and remove hold with lgtm/approved.