feat(runtimes): add Runtimes tab with usage tracking and connection test

Add a new "Runtimes" sidebar tab to manage local agent runtimes with three
main capabilities: runtime status overview, token usage tracking (reading
Claude Code and Codex CLI local JSONL logs via daemon), and an interactive
connection test that sends a ping through the daemon to verify end-to-end
agent CLI connectivity.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/pkg/db/queries/runtime_usage.sql

@@ -0,0 +1,27 @@
+-- name: UpsertRuntimeUsage :exec
+INSERT INTO runtime_usage (runtime_id, date, provider, model, input_tokens, output_tokens, cache_read_tokens, cache_write_tokens)
+VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
+ON CONFLICT (runtime_id, date, provider, model)
+DO UPDATE SET
+    input_tokens = EXCLUDED.input_tokens,
+    output_tokens = EXCLUDED.output_tokens,
+    cache_read_tokens = EXCLUDED.cache_read_tokens,
+    cache_write_tokens = EXCLUDED.cache_write_tokens,
+    updated_at = now();
+
+-- name: ListRuntimeUsage :many
+SELECT * FROM runtime_usage
+WHERE runtime_id = $1
+ORDER BY date DESC
+LIMIT $2;
+
+-- name: GetRuntimeUsageSummary :many
+SELECT provider, model,
+    SUM(input_tokens)::bigint AS total_input_tokens,
+    SUM(output_tokens)::bigint AS total_output_tokens,
+    SUM(cache_read_tokens)::bigint AS total_cache_read_tokens,
+    SUM(cache_write_tokens)::bigint AS total_cache_write_tokens
+FROM runtime_usage
+WHERE runtime_id = $1
+GROUP BY provider, model
+ORDER BY provider, model;