feat: display Extra Usage fuel pack balance in /usage and /status (#1501)

* feat(oauth): parse boosterWallet extra usage from /usages

* feat(oauth): expose extraUsage on AuthManagedUsageResult

* feat(kimi-code): render Extra Usage section in /usage panel

* fix(kimi-code): address Task 3 review feedback for extra usage section

* feat(kimi-code): render Extra Usage section in /status panel

* feat(kimi-code): wire extraUsage into /usage and /status commands

* chore(extra-usage): address final review findings for fuel pack feature

- Update changeset to cover both kimi-code and kimi-code-sdk packages

- Add parser clamp tests and toolkit null-case test

- Replace 'as never' casts in usage-panel tests

- Wrap long import line in status-panel

* chore: temporarily log /usages raw response for debugging

* fix(oauth): accept BOOSTER balance type and drop debug log

* fix(oauth): drop reset hint from Extra Usage and revert periodEnd parsing

* fix(oauth): treat missing amountLeft as zero extra usage and drop debug log

* revert: keep missing amountLeft defaulting to 0 (fully used)

* feat(extra-usage): show monthly cap usage bar and balance in /usage and /status

* fix(extra-usage): show balance and unlimited marker when no monthly cap

* fix(extra-usage): show monthly used with unlimited marker and balance

* fix(extra-usage): label Used and use English Unlimited

* feat(extra-usage): render balance, monthly used and monthly limit as labeled rows

* fix(extra-usage): move Balance row to the bottom

* fix(extra-usage): format currency values with two decimals for column alignment

* fix(extra-usage): right-align currency values so numbers line up

* fix(extra-usage): align currency symbol and decimal point in usage rows

.changeset/expose-extrausage-toolkit.md

@@ -0,0 +1,6 @@
+---
+"@moonshot-ai/kimi-code": patch
+"@moonshot-ai/kimi-code-sdk": patch
+---
+
+Display Extra Usage (fuel pack) balance in `/usage` and `/status` commands.