chore: prepare v0.2.4 release

[Ychris12138]

Prepare v0.2.4 as a focused stability and interaction patch.

Scope

• fix: safely fall back across validated DNS addresses #35 / 在纯 IPv4 或 IPv6 路由不可达环境下，pinnedFetch 固定解析 IPv6 导致 ENETUNREACH / EADDRNOTAVAIL 崩溃 #34 — preserve all DNS answers that pass the existing account-monitor network policy and safely fall back across those pinned candidates when one address family is unreachable. IPv4-only, IPv6-only, WSL2/no-IPv6-route, private-network and fake-IP safety behavior are regression-tested. All validated addresses failing now degrades to a normalized unavailable snapshot instead of escaping the monitor.
• feat: dismiss usage panel on outside click and Escape #36 — dismiss the portaled usage panel when the user clicks outside it or presses Escape, while clicks inside the panel/sidebar badge remain safe. The existing close button is retained in this patch release.
• feat: dismiss usage panel on outside click and Escape #36 — surface only bounded, credential-filtered account diagnostic reasons; localize dns-resolution-failed and all-addresses-unreachable so failures are easier to report without leaking secrets.

Release checks

• version-only diff in package.json / package-lock.json: 0.2.3 → 0.2.4;
• require full CI green on this exact head before merge;
• after merge, require final main CI green before tagging/releasing;
• no feat: inline indicator next to the model selector showing the active session's provider account state #18/feat: 显示当前会话累计 Token 用量与估算费用 #20 current-session feature work or new provider adapters in this patch release.

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.