Add Go daemon-driven VM control plane

Replace the shell-only user workflow with `banger` and `bangerd`: Cobra commands, XDG/SQLite-backed state, managed VM and image lifecycle, and a Bubble Tea TUI for browsing and operating VMs.\n\nKeep Firecracker orchestration behind the daemon so VM specs become persistent objects, and add repo entrypoints for building, installing, and documenting the new flow while still delegating rootfs customization to the existing shell tooling.\n\nHarden the control plane around real usage by reclaiming Firecracker API sockets for the user, restarting stale daemons after rebuilds, and returning the correct `vm.create` payload so the CLI and TUI creation flow work reliably.\n\nValidation: `go test ./...`, `make build`, and a host-side smoke test with `./banger vm create --name codex-smoke`.

internal/firecracker/client.go

@@ -0,0 +1,67 @@
+package firecracker
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+
+	"banger/internal/rpc"
+)
+
+type Client struct {
+	http *http.Client
+}
+
+func New(apiSock string) *Client {
+	return &Client{http: rpc.NewUnixHTTPClient(apiSock)}
+}
+
+func (c *Client) Put(ctx context.Context, path string, body any) error {
+	var payload io.Reader = http.NoBody
+	if body != nil {
+		data, err := json.Marshal(body)
+		if err != nil {
+			return err
+		}
+		payload = bytes.NewReader(data)
+	}
+	req, err := http.NewRequestWithContext(ctx, http.MethodPut, "http://localhost"+path, payload)
+	if err != nil {
+		return err
+	}
+	req.Header.Set("Content-Type", "application/json")
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode >= 300 {
+		data, _ := io.ReadAll(resp.Body)
+		return fmt.Errorf("firecracker %s failed: %s", path, bytes.TrimSpace(data))
+	}
+	return nil
+}
+
+func (c *Client) GetConfig(ctx context.Context) (map[string]any, error) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, "http://localhost/vm/config", nil)
+	if err != nil {
+		return nil, err
+	}
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode >= 300 {
+		data, _ := io.ReadAll(resp.Body)
+		return nil, fmt.Errorf("firecracker config failed: %s", bytes.TrimSpace(data))
+	}
+	var out map[string]any
+	if err := json.NewDecoder(resp.Body).Decode(&out); err != nil {
+		return nil, err
+	}
+	return out, nil
+}