Implement LLM-WP-0008: provider-scoped account balance CLI

Add pluggable balance registry, OpenRouter credits/key limit client,
and llm-connect balance with one-shot --provider that does not change
library defaults.

workplans/LLM-WP-0008-provider-account-balance-cli.md

@@ -4,7 +4,7 @@ type: workplan
 title: "Provider-scoped account balance CLI"
 domain: agents
 repo: llm-connect
-status: ready
+status: finished
 owner: codex
 topic_slug: provider-account-balance-cli
 planning_priority: high
@@ -19,7 +19,7 @@ state_hub_workstream_id: "b8302848-5437-44ad-aec9-5c2df8cd5a47"
 
 # LLM-WP-0008 — Provider-scoped account balance CLI
 
-**status:** ready
+**status:** finished
 **owner:** codex
 
 ## Purpose
@@ -196,7 +196,7 @@ shipping a fake production path.
 
 ```task
 id: LLM-WP-0008-T01
-status: todo
+status: done
 priority: high
 state_hub_task_id: "7df3a274-4ed9-429b-aabc-15fc52c91bfc"
 ```
@@ -208,7 +208,7 @@ Tests: default resolution, unknown provider, unsupported provider.
 
 ```task
 id: LLM-WP-0008-T02
-status: todo
+status: done
 priority: high
 state_hub_task_id: "ff564d7c-5131-4e3e-b0cd-51a41e7a1261"
 ```
@@ -220,7 +220,7 @@ failure of one endpoint). Live smoke optional / manual.
 
 ```task
 id: LLM-WP-0008-T03
-status: todo
+status: done
 priority: high
 state_hub_task_id: "61879d8f-2271-4fa1-9a7b-dbdf7a0d408d"
 ```
@@ -232,7 +232,7 @@ unsupported backends. Tests via mocked client registration.
 
 ```task
 id: LLM-WP-0008-T04
-status: todo
+status: done
 priority: medium
 state_hub_task_id: "9da2c09a-fe32-4602-bcad-5f0f46d4da0f"
 ```
@@ -243,7 +243,7 @@ Note OpenRouter dual signals (account credits vs key limit).
 
 ```task
 id: LLM-WP-0008-T05
-status: todo
+status: done
 priority: low
 state_hub_task_id: "ebf67737-3f3d-458b-9dec-9224f08c8016"
 ```
@@ -255,18 +255,18 @@ within rounding of OpenRouter dashboard figures; document any known drift
 
 ## Acceptance
 
-- [ ] `llm-connect balance` reports OpenRouter remaining budget when default
+- [x] `llm-connect balance` reports OpenRouter remaining budget when default
       provider is `openrouter`, without changing any defaults
-- [ ] `llm-connect balance --provider openrouter` same result; still no default
+- [x] `llm-connect balance --provider openrouter` same result; still no default
       mutation
-- [ ] `llm-connect balance --provider <unsupported>` fails clearly (not with
+- [x] `llm-connect balance --provider <unsupported>` fails clearly (not with
       OpenRouter data)
-- [ ] Account credits remaining and key limit remaining are distinguishable in
+- [x] Account credits remaining and key limit remaining are distinguishable in
       output when both are available
-- [ ] EUR amounts shown when FX available
-- [ ] Adding a future provider is “register a balance client”, not hard-coding
+- [x] EUR amounts shown when FX available
+- [x] Adding a future provider is “register a balance client”, not hard-coding
       OpenRouter into the CLI command body
-- [ ] Offline unit tests pass without network
+- [x] Offline unit tests pass without network
 
 ## Risks / notes
 
@@ -285,3 +285,14 @@ within rounding of OpenRouter dashboard figures; document any known drift
 ## Implementation order
 
 T01 → T02 → T03 → T04 → T05.
+
+
+## Implementation notes (2026-08-03)
+
+- Added `llm_connect.balance` with pluggable registry; OpenRouter client uses
+  `/api/v1/credits` + `/api/v1/auth/key` via new `get_json` HTTP helper.
+- CLI: `llm-connect balance [--provider] [--json] [--eur-per-usd]`.
+- Live smoke: account credits remaining ~12.72 USD and key limit remaining
+  ~9.98 USD; unsupported `gemini` exits 2; defaults unchanged
+  (`openrouter` / `moonshotai/kimi-k3`).
+- Unit suite: 237 passed.