fix(#14,#16): stub mode for executeWorkStreaming + SSE race condition

Fix #14 — AgentService stub mode for executeWorkStreaming:
- Remove static import of @workspace/integrations-anthropic-ai (throws on
  module load when env vars absent)
- Add STUB_MODE detection at startup using AI_INTEGRATIONS_ANTHROPIC_API_KEY
  and AI_INTEGRATIONS_ANTHROPIC_BASE_URL presence
- Lazy getClient() uses dynamic import, only called in live mode
- stub executeWork() and executeWorkStreaming() return canned responses;
  streaming stub emits word-by-word with 40 ms delay to exercise SSE path
- Define local AnthropicLike interface — no dependency on @anthropic-ai/sdk
  types or unbuilt integrations-anthropic-ai dist

Fix #16 — SSE stream registry race condition:
- After bus-listener wait, refresh BOTH stream registry AND job state from DB
- If job completed while waiting (stream already gone), replay full result
  immediately instead of emitting 'Stream not available' error
- Increase wait timeout from 60 s to 90 s for mainnet payment latency
- Cleaner event bus filter: any jobId event resolves the wait (not just
  job:state and job:paid) so job:completed also unblocks waiting clients
- Named branches with comments for each resolution path

Fix pre-existing typecheck errors (bonus):
- event-bus.ts: EventEmitter overload uses any[] not unknown[]
- testkit.ts: escape bash ${ELAPSED_T14} in TS template literal

artifacts/api-server/src/routes/testkit.ts

@@ -383,7 +383,7 @@ if [[ -n "$SESSION_MACAROON" && "$SESSION_MACAROON" != "null" ]]; then
   END_T14=$(date +%s)
   ELAPSED_T14=$((END_T14 - START_T14))
   if [[ "$T14_CODE" == "200" && ("$T14_STATE" == "complete" || "$T14_STATE" == "rejected") && -n "$T14_DEBITED" && "$T14_DEBITED" != "null" && -n "$T14_BAL" ]]; then
-    note PASS "state=$T14_STATE in ${ELAPSED_T14}s, debitedSats=$T14_DEBITED, balanceRemaining=$T14_BAL"
+    note PASS "state=$T14_STATE in \${ELAPSED_T14}s, debitedSats=$T14_DEBITED, balanceRemaining=$T14_BAL"
     PASS=$((PASS+1))
   else
     note FAIL "code=$T14_CODE body=$T14_BODY"