fix(agent): count bounded auxiliary usage in root token scope

Problem: an explicitly bounded Agent root omitted reviewer/advisor usage
already emitted by the shared bounded-call terminal, allowing extra rounds.

Root cause: normal-round accounting does not own auxiliary request usage.

Fix: connect the bounded terminal to one copied, replaceable context
observer bound to the original root counter. Preserve job cancellation,
normal telemetry, missing usage and zero-limit behavior.

Verification: all 239 root packages pass in disjoint commands; nine complete
owner/caller race suites and real boot HTTP/SSE regressions pass. Exact old
owners reproduce the gap; selected accepted auxiliary composition passes.
Formatting, vet, lint, repository checks and eight cross-compiles pass.
The 20-event Windows contract is locally verified, not native execution.

.github/workflows/ci.yml

@@ -452,6 +452,41 @@ jobs:
           if-no-files-found: ignore
           retention-days: 7
 
+      - name: test (Windows bounded root budget)
+        if: env.RUN_STEPS == 'true' && runner.os == 'Windows' && github.event_name == 'pull_request'
+        timeout-minutes: 5
+        shell: bash
+        run: |
+          set -o pipefail
+          go test -count=1 -timeout=3m -json -run '^Test(AuxiliaryUsageObserver|BoundedUsageObserver|RootBounded|EffectRootBounded)' ./internal/contract/provider ./internal/model/boundedllm ./internal/runtime/agent ./internal/assembly/boot | tee "$RUNNER_TEMP/bounded-root-budget.jsonl"
+          jq -se '
+            [.[] | select(.Test == null and .Action == "pass") | .Package] as $packages |
+            [.[] | select(.Test != null and .Action == "pass") | .Test] as $tests |
+            all(.[]; .Action != "skip" and .Action != "fail") and
+            (["reasonix/internal/contract/provider", "reasonix/internal/model/boundedllm",
+              "reasonix/internal/runtime/agent", "reasonix/internal/assembly/boot"] - $packages | length) == 0 and
+            (["TestAuxiliaryUsageObserverReplacesAndCopies",
+              "TestBoundedUsageObserverOwnsOneTerminal", "TestBoundedUsageObserverOwnsOneTerminal/reported",
+              "TestBoundedUsageObserverOwnsOneTerminal/billed_failure", "TestBoundedUsageObserverOwnsOneTerminal/without_sink",
+              "TestBoundedUsageObserverOwnsOneTerminal/missing", "TestBoundedUsageObserverOwnsOneTerminal/input_refused",
+              "TestRootBoundedReviewerBudget", "TestRootBoundedReviewerBudget/reported",
+              "TestRootBoundedReviewerBudget/billed_failure", "TestRootBoundedReviewerBudget/missing_usage",
+              "TestRootBoundedReviewerBudget/disabled", "TestRootBoundedReviewerBudget/no_emission",
+              "TestRootBoundedReviewerBudget/projected_job_context", "TestRootBoundedNestedBudgetChargesOnce",
+              "TestRootBoundedLateProjectionStaysWithOldTask", "TestEffectRootBoundedAdvisorBudget",
+              "TestEffectRootBoundedAdvisorBudget/reported", "TestEffectRootBoundedAdvisorBudget/disabled",
+              "TestEffectRootBoundedAdvisorBudget/missing_usage"] - $tests | length) == 0
+          ' "$RUNNER_TEMP/bounded-root-budget.jsonl"
+
+      - name: upload Windows bounded root budget inventory
+        if: always() && env.RUN_STEPS == 'true' && runner.os == 'Windows' && github.event_name == 'pull_request'
+        uses: actions/upload-artifact@cf430e030ddbb5b0abf93d22962f4752f3646cd9 # v7
+        with:
+          name: bounded-root-budget-windows-${{ github.run_attempt }}
+          path: ${{ runner.temp }}/bounded-root-budget.jsonl
+          if-no-files-found: ignore
+          retention-days: 7
+
       # The general Windows PR smoke list intentionally omits internal/contract/tool.
       # Keep the session-temp portability contract covered without widening the
       # leg to every tool test: two real PowerShell launches must share the