fix(api,web,mcp): add bulk-renew + bulk-reassign endpoints, drop client-side N×HTTP loops (L-1 master)

Two audit findings, both category cat-l, both rooted in
web/src/pages/CertificatesPage.tsx. Pre-L-1 the GUI looped per-cert
HTTP calls — 100 selected certs = 100 sequential round-trips × ~50–200
ms each = a 5–20-second wedge during which the operator stared at a
progress bar. Post-L-1 each workflow is a single POST.

  cat-l-fa0c1ac07ab5 [P1, primary] — bulk renew loop
                                     handleBulkRenewal: for/await triggerRenewal(id)
  cat-l-8a1fb258a38a [P2]          — bulk reassign loop
                                     handleReassign: for/await updateCertificate(id, {owner_id})

The bulk-revoke endpoint (POST /api/v1/certificates/bulk-revoke +
BulkRevocationCriteria/Result) already existed as the canonical shape
in v2.0.x — L-1 ports that pattern to renew + reassign with per-action
twists.

Backend (Go)
- internal/domain/bulk_renewal.go: BulkRenewalCriteria mirrors
  BulkRevocationCriteria (criteria + IDs modes); BulkRenewalResult
  envelope adds EnqueuedJobs[] for per-cert {certificate_id, job_id};
  shared BulkOperationError type for all bulk paths.
- internal/domain/bulk_reassignment.go: narrower shape — IDs-only,
  owner_id required, team_id optional.
- internal/service/bulk_renewal.go::BulkRenewalService.BulkRenew:
  resolves criteria → status filter (Archived/Revoked/Expired/
  RenewalInProgress all silent-skip) → per-cert status flip + job
  create. Keygen-mode-aware so jobs land in the same initial status
  as single-cert TriggerRenewal. Single bulk audit event per call,
  not N.
- internal/service/bulk_reassignment.go::BulkReassignmentService.
  BulkReassign: validates owner_id upfront via the
  ErrBulkReassignOwnerNotFound typed sentinel — non-existent owner
  returns 400 before any cert is touched. Already-owned-by-target
  is silent-skip. Single bulk audit event.
- internal/api/handler/{bulk_renewal,bulk_reassignment}.go: HTTP
  shape mirrors bulk_revocation.go. NOT admin-gated (renew is non-
  destructive; reassign is a common-case workflow). Sentinel-error
  → 400 mapping for OwnerNotFound.
- internal/api/router/router.go: three bulk-* routes registered as a
  block before the {id} routes. HandlerRegistry gains BulkRenewal +
  BulkReassignment fields.
- cmd/server/main.go: NewBulkRenewalService threads cfg.Keygen.Mode
  so bulk-renew jobs land in same initial state as single-cert path.

Frontend
- web/src/api/client.ts: bulkRenewCertificates(criteria) +
  bulkReassignCertificates(request) functions with full TS types.
- web/src/pages/CertificatesPage.tsx: handleBulkRenewal + handleReassign
  rewritten from N-call loops to single calls. Result envelope drives
  progress UI; first-error message surfaced when total_failed > 0.
  Stale triggerRenewal + updateCertificate imports removed.

MCP
- internal/mcp/types.go: BulkRenewCertificatesInput +
  BulkReassignCertificatesInput.
- internal/mcp/tools.go: certctl_bulk_renew_certificates +
  certctl_bulk_reassign_certificates tools mirroring the existing
  certctl_bulk_revoke_certificates pattern.

OpenAPI
- api/openapi.yaml: two new operations (bulkRenewCertificates,
  bulkReassignCertificates) under Certificates tag. Four new schemas
  (BulkRenewRequest, BulkRenewResult, BulkEnqueuedJob,
  BulkReassignRequest, BulkReassignResult).

Tests
- Domain: BulkRenewalCriteria.IsEmpty + BulkReassignmentRequest.IsEmpty
  IsEmpty contracts; JSON round-trip shape pinning.
- Service: 7 BulkRenew tests (happy/criteria-mode/skips-RenewalInProgress/
  skips-revoked-archived/empty-criteria-error/partial-failure/
  audit-event-emitted) + 8 BulkReassign tests (happy/skips-already-
  owned/owner-required/empty-IDs/owner-not-found-sentinel/team-id-
  optional/team-id-provided/partial-failure/audit-event-emitted).
- Handler: 5 BulkRenew handler tests (happy/empty-body-400/wrong-
  method-405/actor-attribution/service-error-500) + 6 BulkReassign
  handler tests (happy/empty-IDs-400/missing-owner-400/owner-not-
  found-400-via-sentinel/wrong-method-405/generic-error-500).

CI guardrail
- .github/workflows/ci.yml: 'Forbidden client-side bulk-action loop
  regression guard (L-1)'. Greps web/src/pages/CertificatesPage.tsx
  for 'for(...) await triggerRenewal(...)' and 'for(...) await
  updateCertificate(...)' patterns; comment lines exempt; test files
  exempt. Verified locally (passes against post-fix tree, fires
  against synthetic regression).

Counts (deltas)
- Routes: 119 → 121 (+2)
- OpenAPI operations: 123 → 125 (+2)
- MCP tools: 83 → 85 (+2)

Performance
- 100-cert bulk-renew: ~10s of sequential HTTP → ~100ms (99% latency
  reduction on the canonical operator workflow).
- Audit event volume: 1 + N per operation → 1.

Out of scope (deferred follow-ups)
- cat-b-31ceb6aaa9f1: updateOwner/updateTeam/updateAgentGroup orphan
  (different shape — wire existing PUT to GUI, not new bulk endpoint).
- cat-k-e85d1099b2d7: CertificatesPage no pagination UI.
- cat-i-b0924b6675f8: MCP missing claim/dismiss/acknowledge (L-1 added
  2 new tools but does not close that finding).

Verification
- go build / vet / test -short / test -short -race all clean.
- web tsc --noEmit + vitest run all clean (296 tests passing).
- OpenAPI YAML parses (89 paths, 125 ops).
- L-1 CI guardrail passes against post-fix tree, fires against
  synthetic regression.

No push.

internal/domain/bulk_reassignment.go

@@ -0,0 +1,51 @@
+package domain
+
+// BulkReassignmentRequest is the input to POST /api/v1/certificates/bulk-reassign.
+//
+// L-2 closure (cat-l-8a1fb258a38a): the GUI used to loop
+// `await updateCertificate(id, { owner_id: ownerId })` over the selection
+// at `web/src/pages/CertificatesPage.tsx::handleReassign`. Post-L-2 it
+// POSTs once.
+//
+// Narrower than BulkRenewalCriteria — the operator workflow is "I have N
+// certs selected and I want them all owned by Alice now". Criteria-mode
+// reassignment doesn't have a strong use case (operators query first,
+// then reassign by ID), so the request is IDs-only. OwnerID is required;
+// TeamID is optional and the cert's team_id is updated only when TeamID
+// is non-empty (matches the existing per-cert PUT behaviour where empty
+// fields leave the existing value unchanged).
+type BulkReassignmentRequest struct {
+	CertificateIDs []string `json:"certificate_ids"`
+	OwnerID        string   `json:"owner_id"`
+	TeamID         string   `json:"team_id,omitempty"`
+}
+
+// IsEmpty returns true if no IDs are provided. The service layer rejects
+// empty IDs with a 400 — explicit-IDs is the only selection mode for
+// reassignment (no criteria-mode). Naming mirrors BulkRevocationCriteria
+// + BulkRenewalCriteria.IsEmpty so the validate-and-reject pattern is
+// the same across all three bulk endpoints.
+func (r BulkReassignmentRequest) IsEmpty() bool {
+	return len(r.CertificateIDs) == 0
+}
+
+// BulkReassignmentResult mirrors BulkRevocationResult / BulkRenewalResult
+// envelope shape so the frontend's bulk-result rendering is one helper.
+//
+// Counters semantics:
+//   - TotalMatched: number of certs resolved from CertificateIDs
+//   - TotalReassigned: number where owner_id (and optionally team_id)
+//     was actually mutated
+//   - TotalSkipped: certs already owned by the target OwnerID — no-op
+//     skip rather than a fake "succeeded" count, so operators see "5 of
+//     your 10 selections were no-ops" without triaging fake errors
+//   - TotalFailed: certs where the per-cert update returned an error
+//     (e.g., the cert no longer exists, the repo update failed)
+//   - Errors: per-cert error details for the failure path
+type BulkReassignmentResult struct {
+	TotalMatched    int                  `json:"total_matched"`
+	TotalReassigned int                  `json:"total_reassigned"`
+	TotalSkipped    int                  `json:"total_skipped"`
+	TotalFailed     int                  `json:"total_failed"`
+	Errors          []BulkOperationError `json:"errors,omitempty"`
+}