fix: stabilize pet proactive reminders after restart

[hazy-cloudy]

Closes #258

问题

• 一次性 pet reminder 在重启后会因为旧 session 失效而收不到
• 一次性 at 任务在应用重启后如果已经过点，会直接失去执行机会
• progress_nudge 需要和 cron/every 周期任务区分

改动

• 补齐 weekly_report / progress_nudge 的后端最小闭环
• 修复一次性 reminder 的 session fallback、deferred retry、过点重启继续执行
• 按 session_id 定向投递 pet proactive push
• 增加活动沉淀、debug action 和 scripts/test-pet-proactive.ps1
• 修复打包后 Electron 启动与 asar 布局兼容性

验证

• go test ./pkg/cron -run "TestCronService_(ComputeNextRun|ExecutionFlow|ExecuteJobDeferredKeepsOneTimeJobForRetry|StartRunsOverdueOneTimeJobAfterReload|DedupOneTimeJob)"
• go test ./pkg/tools -run "TestCronTool_ExecuteJob"
• go test ./pkg/pet -run TestDoesNotExist
• 本地 win-unpacked 可启动 ClawPet.exe

[fennoai]

I found four issues worth addressing:

1. pkg/pet/config/loader.go: Load() now prints cfg.Voice.ASRModelList before the later cfg.Voice == nil defaulting block. Older or minimal pet_config.json files can still omit voice, so this path will panic during startup.

2. pkg/pet/service.go: the new active-session tracking can still go stale. UnregisterSession() only clears activeSessionID when all connections are gone, so if the last active pet websocket closes while another session stays connected, reminder delivery can still resolve to the dead session instead of deferring.

3. pkg/pet/service.go / pkg/pet/proactive/snapshot.go: the proactive snapshot wiring does not populate the new runtime session fields such as ActiveSessionID, CurrentSessionBusy, ConsoleVisible, or PetVisible. That leaves the session-aware selection path in ProgressNudgeProvider and part of the interruptibility logic effectively inactive in production even though the tests set those fields manually.

4. pkg/pet/report/aggregator.go: the summary literals in buildSummary() are mojibake, so generated weekly reports will contain garbled Chinese text.

I also ran go test ./pkg/pet/proactive ./pkg/cron ./pkg/tools; the first two passed, while pkg/tools still has existing web-tool test failures unrelated to this PR.

[hazy-cloudy]

上述问题已解决