feat: wire context-window-recovery callers to async SDK/HTTP variants on SQLite

- empty-content-recovery: isSqliteBackend() branch delegating to extracted
  empty-content-recovery-sdk.ts with SDK message scanning
- message-builder: sanitizeEmptyMessagesBeforeSummarize now async with SDK path
  using replaceEmptyTextPartsAsync/injectTextPartAsync
- target-token-truncation: truncateUntilTargetTokens now async with SDK path
  using findToolResultsBySizeFromSDK/truncateToolResultAsync
- aggressive-truncation-strategy: passes client to truncateUntilTargetTokens
- summarize-retry-strategy: await sanitizeEmptyMessagesBeforeSummarize
- client.ts: derive Client from PluginInput['client'] instead of manual defs
- executor.test.ts: .mockReturnValue() → .mockResolvedValue() for async fns
- storage.test.ts: add await for async truncateUntilTargetTokens

src/hooks/anthropic-context-window-limit-recovery/executor.test.ts

@@ -313,7 +313,7 @@ describe("executeCompact lock management", () => {
       maxTokens: 200000,
     })
 
-    const truncateSpy = spyOn(storage, "truncateUntilTargetTokens").mockReturnValue({
+    const truncateSpy = spyOn(storage, "truncateUntilTargetTokens").mockResolvedValue({
       success: true,
       sufficient: false,
       truncatedCount: 3,
@@ -354,7 +354,7 @@ describe("executeCompact lock management", () => {
       maxTokens: 200000,
     })
 
-    const truncateSpy = spyOn(storage, "truncateUntilTargetTokens").mockReturnValue({
+    const truncateSpy = spyOn(storage, "truncateUntilTargetTokens").mockResolvedValue({
       success: true,
       sufficient: true,
       truncatedCount: 5,