feat: add CLI commands for usage analysis, cost breakdown, and setup

Implement the complete Cobra command tree (11 subcommands):

- cmd/root.go: Root command with persistent flags (--days, --project,
  --model, --no-cache, --data-dir, --quiet, --no-subagents). Shared
  loadData() orchestrates the full pipeline: tries cache-assisted
  loading first, falls back to uncached parse on cache failure,
  reports progress to stderr. applyFilters() applies project/model
  substring filters and computes the time window.

- cmd/summary.go: Default command (also "cburn summary"). Renders a
  bordered metrics table with token breakdown (5 types), cost with
  cache savings, and per-day rates with period-over-period deltas.

- cmd/costs.go: Detailed cost analysis — breaks down costs by token
  type (output, cache_write_1h, input, cache_write_5m, cache_read)
  with share percentages, period comparison bar chart, and per-model
  cost breakdown (input/output/cache/total columns).

- cmd/daily.go: Daily usage table (date, weekday, sessions, prompts,
  tokens, cost) sorted most-recent-first.

- cmd/hourly.go: Activity heatmap showing prompt distribution across
  24 hours with Unicode block bars, reports peak hour.

- cmd/models.go: Model usage ranking with API call counts, token
  volumes, cost, and usage share percentage.

- cmd/projects.go: Project ranking by cost with session/prompt/token
  counts.

- cmd/sessions.go: Session list sorted by recency with --limit flag
  (default 20). Shows start time, project, duration, tokens, cost.
  Marks subagent sessions with "(sub)" suffix.

- cmd/config_cmd.go: Displays current configuration across all
  sections (general, admin API, appearance, budget) with auto-
  detected plan ceiling.

- cmd/setup.go: Interactive first-run wizard — configures Admin API
  key, default time range (7/30/90 days), and color theme (Flexoki
  Dark, Catppuccin Mocha, Tokyo Night, Terminal). Saves to
  ~/.config/cburn/config.toml.

- cmd/tui.go: Launches the interactive Bubble Tea TUI dashboard,
  passing through all filter flags and applying the configured theme.

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

cmd/summary.go

@@ -0,0 +1,95 @@
+package cmd
+
+import (
+	"fmt"
+	"os"
+
+	"cburn/internal/cli"
+	"cburn/internal/pipeline"
+
+	"github.com/spf13/cobra"
+)
+
+var summaryCmd = &cobra.Command{
+	Use:   "summary",
+	Short: "Detailed usage summary with costs",
+	RunE:  runSummary,
+}
+
+func init() {
+	rootCmd.AddCommand(summaryCmd)
+}
+
+func runSummary(_ *cobra.Command, _ []string) error {
+	result, err := loadData()
+	if err != nil {
+		return err
+	}
+
+	if len(result.Sessions) == 0 {
+		fmt.Println("\n  No Claude Code sessions found.")
+		fmt.Println("  Use Claude Code first, then come back!")
+		return nil
+	}
+
+	filtered, since, until := applyFilters(result.Sessions)
+	stats := pipeline.Aggregate(filtered, since, until)
+
+	if stats.TotalSessions == 0 {
+		fmt.Println("\n  No sessions found in the selected time range.")
+		return nil
+	}
+
+	// Compute previous period for comparison
+	prevDuration := until.Sub(since)
+	prevSince := since.Add(-prevDuration)
+	prevStats := pipeline.Aggregate(filtered, prevSince, since)
+
+	// Render output
+	fmt.Println()
+	fmt.Println(cli.RenderTitle(fmt.Sprintf("CLAUDE USAGE  Last %dd", flagDays)))
+	fmt.Println()
+
+	// Build the summary table
+	rows := [][]string{
+		{"Sessions", cli.FormatNumber(int64(stats.TotalSessions))},
+		{"Prompts", cli.FormatNumber(int64(stats.TotalPrompts))},
+		{"Total Time", cli.FormatDuration(stats.TotalDurationSecs)},
+		{"---"},
+		{"Input Tokens", cli.FormatTokens(stats.InputTokens)},
+		{"Output Tokens", cli.FormatTokens(stats.OutputTokens)},
+		{"Cache Write (5m)", cli.FormatTokens(stats.CacheCreation5mTokens)},
+		{"Cache Write (1h)", cli.FormatTokens(stats.CacheCreation1hTokens)},
+		{"Cache Read", cli.FormatTokens(stats.CacheReadTokens)},
+		{"Total Billed", cli.FormatTokens(stats.TotalBilledTokens)},
+		{"---"},
+		{"Cost (est)", cli.FormatCost(stats.EstimatedCost)},
+		{"Cache Savings", cli.FormatCost(stats.CacheSavings)},
+		{"Cache Hit Rate", cli.FormatPercent(stats.CacheHitRate)},
+		{"---"},
+	}
+
+	// Cost per day with delta
+	costDayStr := fmt.Sprintf("%s/day", cli.FormatCost(stats.CostPerDay))
+	if prevStats.CostPerDay > 0 {
+		costDayStr += fmt.Sprintf("  (%s vs prev %dd)",
+			cli.FormatDelta(stats.CostPerDay, prevStats.CostPerDay), flagDays)
+	}
+	rows = append(rows, []string{"Cost/day", costDayStr})
+	rows = append(rows, []string{"Tokens/day", cli.FormatTokens(stats.TokensPerDay)})
+	rows = append(rows, []string{"Sessions/day", fmt.Sprintf("%.1f", stats.SessionsPerDay)})
+
+	table := cli.Table{
+		Headers: []string{"Metric", "Value"},
+		Rows:    rows,
+	}
+
+	fmt.Print(cli.RenderTable(table))
+
+	// Print warnings
+	if result.FileErrors > 0 {
+		fmt.Fprintf(os.Stderr, "\n  %d files could not be parsed\n", result.FileErrors)
+	}
+
+	return nil
+}