feat: add performance controls for large browser ops

- Add throttled large-operation handling for tab, group, and session commands.
- Introduce performance profiles, audible-tab aware gentle mode, and job progress tracking.
- Support background session restores with status/cancel commands and lazy placeholders.
- Expose new perf and extension CLI groups plus matching Python SDK methods.
- Preserve pinned tabs during session snapshots and debounce auto-save updates.
- Bump browser-cli and extension versions to 0.10.0 and add pytest-cov to dev deps.
- Add coverage for performance controls, background jobs, lazy restores, and tab metadata.

tests/test_extension_error_page_handling.py

@@ -35,3 +35,106 @@ def test_navigation_and_tabs_report_browser_error_pages():
     assert "last URL:" in tabs
     assert "isBrowserErrorUrl" in navigation
     assert "showing an error page while waiting for load" in navigation
+
+def test_large_extension_operations_yield_between_batches():
+    core = (ROOT / "extension" / "src" / "core.ts").read_text()
+    tabs = (ROOT / "extension" / "src" / "commands" / "tabs.ts").read_text()
+    groups = (ROOT / "extension" / "src" / "commands" / "groups.ts").read_text()
+    session = (ROOT / "extension" / "src" / "commands" / "session.ts").read_text()
+
+    assert "yieldForLargeOperation" in core
+    assert "getLargeOperationThrottle" in core
+    assert "hasAudibleTabs" in core
+    assert "runLargeOperation" in core
+    assert "largeOperationQueue" in core
+    assert "updateJobProgress" in core
+    assert "throwIfJobCancelled" in core
+    assert "getPerformanceProfile" in core
+    assert "setPerformanceProfile" in core
+    assert "GENTLE_OPERATION_BATCH_SIZE" in core
+    assert "GENTLE_OPERATION_PAUSE_MS" in core
+    assert "itemCount >= 300" in core
+    assert "itemCount >= 100" in core
+    assert "chrome.tabs.query({ audible: true })" in core
+    assert "yieldForLargeOperation" in tabs
+    assert "toClose.slice" in tabs
+    assert "ids.slice" in tabs
+    assert "w.tabs.every" in tabs
+    assert "getLargeOperationThrottle" in tabs
+    assert "runLargeOperation(\"tabs.sort\"" in tabs
+    assert "yieldForLargeOperation" in groups
+    assert "tabIds.slice" in groups
+    assert "getLargeOperationThrottle" in groups
+    assert "runLargeOperation(\"group.close\"" in groups
+    assert "yieldForLargeOperation(createdTabs.length" in session
+    assert "getLargeOperationThrottle" in session
+    assert "runLargeOperation(\"session.load\"" in session
+    assert "chrome.tabs.discard" in session
+    assert "lazyPlaceholderUrl" in session
+    assert "activateLazyTab" in session
+    assert "lazySessionTabs" in session
+    assert "throwIfJobCancelled" in session
+    assert "updateJobProgress" in session
+
+    index = (ROOT / "extension" / "src" / "index.ts").read_text()
+    assert "BACKGROUND_COMMANDS" in index
+    assert "startBackgroundJob" in index
+    assert "persistJobs" in index
+    assert "recentJobs" in index
+    assert "jobs.status" in index
+    assert "jobs.cancel" in index
+    assert "perf.status" in index
+    assert "perf.set_profile" in index
+    assert "__background" in index
+
+
+def test_session_autosave_is_debounced_and_non_overlapping():
+    session = (ROOT / "extension" / "src" / "commands" / "session.ts").read_text()
+
+    assert "autoSaveTimer" in session
+    assert "autoSaveInFlight" in session
+    assert "autoSavePending" in session
+    assert "scheduleAutoSave" in session
+    assert "autoSaveUpdatedHandler" in session
+    assert "saveAutoSessionIfChanged" in session
+    assert "sessionSignature" in session
+    assert "autoSaveSignature" in session
+    assert "chrome.tabs.onUpdated.addListener(autoSaveUpdatedHandler)" in session
+    assert "chrome.tabs.onCreated.addListener(autoSaveHandler)" in session
+    assert "chrome.tabs.onMoved.addListener(autoSaveHandler)" in session
+    assert "if (!(\"url\" in changeInfo)) return;" in session
+    assert "setTimeout(runAutoSave, delayMs)" in session
+    assert "clearTimeout(autoSaveTimer)" in session
+
+
+def test_cli_and_sdk_expose_gentle_restore_controls():
+    session_cli = (ROOT / "browser_cli" / "commands" / "session.py").read_text()
+    tabs_cli = (ROOT / "browser_cli" / "commands" / "tabs.py").read_text()
+    groups_cli = (ROOT / "browser_cli" / "commands" / "groups.py").read_text()
+    sdk = (ROOT / "browser_cli" / "__init__.py").read_text()
+
+    assert "--gentle-mode" in session_cli
+    assert "--discard-background-tabs" in session_cli
+    assert "--background" in session_cli
+    assert "--lazy" in session_cli
+    assert "--eager-tabs" in session_cli
+    assert "job-status" in session_cli
+    assert "job-cancel" in session_cli
+    assert "discardBackgroundTabs" in session_cli
+    assert "--gentle-mode" in tabs_cli
+    assert "gentleMode" in tabs_cli
+    assert "--gentle-mode" in groups_cli
+    assert "discard_background_tabs" in sdk
+    assert "discardBackgroundTabs" in sdk
+    assert "session_load_background" in sdk
+    assert "job_status" in sdk
+    assert "job_cancel" in sdk
+    assert "perf_status" in sdk
+    assert "set_performance_profile" in sdk
+
+    perf_cli = (ROOT / "browser_cli" / "commands" / "perf.py").read_text()
+    root_cli = (ROOT / "browser_cli" / "cli.py").read_text()
+    assert "perf_group" in perf_cli
+    assert "perf.status" in perf_cli
+    assert "perf.set_profile" in perf_cli
+    assert "main.add_command(perf_group)" in root_cli