Add Claude integration to dashboard

Add comprehensive Claude Code monitoring and realtime streaming to the K8s dashboard.
Includes API endpoints for health, stats, summary, inventory, and live event streaming.
Frontend provides overview, usage, inventory, debug, and live feed views.

dashboard/internal/api/claude_handlers.go

@@ -0,0 +1,162 @@
+package api
+
+import (
+	"net/http"
+	"path/filepath"
+
+	"github.com/will/k8s-agent-dashboard/internal/claude"
+)
+
+// ClaudeLoader is a minimal interface for Claude Ops endpoints.
+//
+// Keep it small so handlers are easy to test with fakes.
+type ClaudeLoader interface {
+	ClaudeDir() string
+	LoadStatsCache() (*claude.StatsCache, error)
+	ListDir(name string) ([]claude.DirEntry, error)
+	FileMeta(relPath string) (claude.FileMeta, error)
+	PathExists(relPath string) bool
+}
+
+func GetClaudeStats(loader ClaudeLoader) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		stats, err := loader.LoadStatsCache()
+		if err != nil {
+			respondError(w, http.StatusInternalServerError, err.Error())
+			return
+		}
+		respondJSON(w, http.StatusOK, stats)
+	}
+}
+
+type ClaudeSummaryResponse struct {
+	Totals   ClaudeSummaryTotals          `json:"totals"`
+	PerModel map[string]claude.ModelUsage `json:"perModel"`
+	Derived  ClaudeSummaryDerived         `json:"derived"`
+}
+
+type ClaudeSummaryTotals struct {
+	TotalSessions int `json:"totalSessions"`
+	TotalMessages int `json:"totalMessages"`
+}
+
+type ClaudeSummaryDerived struct {
+	CacheHitRatioEstimate  float64 `json:"cacheHitRatioEstimate"`
+	TopModelByOutputTokens string  `json:"topModelByOutputTokens"`
+}
+
+func GetClaudeSummary(loader ClaudeLoader) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		stats, err := loader.LoadStatsCache()
+		if err != nil {
+			respondError(w, http.StatusInternalServerError, err.Error())
+			return
+		}
+
+		resp := ClaudeSummaryResponse{
+			Totals: ClaudeSummaryTotals{
+				TotalSessions: stats.TotalSessions,
+				TotalMessages: stats.TotalMessages,
+			},
+			PerModel: stats.ModelUsage,
+		}
+
+		var inputTokens, cacheRead, cacheCreate int
+		maxOut := -1
+		topModel := ""
+		for model, usage := range stats.ModelUsage {
+			inputTokens += usage.InputTokens
+			cacheRead += usage.CacheReadInputTokens
+			cacheCreate += usage.CacheCreationInputTokens
+			if usage.OutputTokens > maxOut {
+				maxOut = usage.OutputTokens
+				topModel = model
+			}
+		}
+
+		den := float64(inputTokens + cacheRead + cacheCreate)
+		ratio := 0.0
+		if den > 0 {
+			ratio = float64(cacheRead) / den
+		}
+
+		resp.Derived = ClaudeSummaryDerived{
+			CacheHitRatioEstimate:  ratio,
+			TopModelByOutputTokens: topModel,
+		}
+
+		respondJSON(w, http.StatusOK, resp)
+	}
+}
+
+func GetClaudeHealth(loader ClaudeLoader) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		checks := map[string]bool{}
+		missing := false
+		for _, rel := range []string{"stats-cache.json", "history.jsonl", filepath.Join("state", "component-registry.json")} {
+			exists := loader.PathExists(rel)
+			checks[rel] = exists
+			if !exists {
+				missing = true
+			}
+		}
+
+		status := "ok"
+		if missing {
+			status = "degraded"
+		}
+
+		respondJSON(w, http.StatusOK, map[string]any{
+			"status":     status,
+			"claudeDir":  loader.ClaudeDir(),
+			"fileChecks": checks,
+		})
+	}
+}
+
+func GetClaudeInventory(loader ClaudeLoader) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		agents, err := loader.ListDir("agents")
+		if err != nil {
+			respondError(w, http.StatusInternalServerError, err.Error())
+			return
+		}
+		skills, err := loader.ListDir("skills")
+		if err != nil {
+			respondError(w, http.StatusInternalServerError, err.Error())
+			return
+		}
+		commands, err := loader.ListDir("commands")
+		if err != nil {
+			respondError(w, http.StatusInternalServerError, err.Error())
+			return
+		}
+
+		respondJSON(w, http.StatusOK, map[string]any{
+			"agents":   agents,
+			"skills":   skills,
+			"commands": commands,
+		})
+	}
+}
+
+func GetClaudeDebugFiles(loader ClaudeLoader) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		var metas []claude.FileMeta
+		for _, rel := range []string{
+			"stats-cache.json",
+			"history.jsonl",
+			filepath.Join("state", "component-registry.json"),
+		} {
+			meta, err := loader.FileMeta(rel)
+			if err != nil {
+				respondError(w, http.StatusInternalServerError, err.Error())
+				return
+			}
+			metas = append(metas, meta)
+		}
+		respondJSON(w, http.StatusOK, map[string]any{
+			"files": metas,
+		})
+	}
+}