Updated the README

Added new security layers

internal/index/index.go

@@ -6,17 +6,14 @@ import (
 	"time"
 )
 
-// Entry is the API/JSON shape the server returns.
-// StoredAt is RFC3339/RFC3339Nano in UTC.
 type Entry struct {
 	Hash      string `json:"hash"`
 	Bytes     int64  `json:"bytes"`
-	StoredAt  string `json:"stored_at"` // RFC3339( Nano ) string
+	StoredAt  string `json:"stored_at"`
 	Private   bool   `json:"private"`
-	CreatorTZ string `json:"creator_tz,omitempty"` // IANA TZ like "America/New_York"
+	CreatorTZ string `json:"creator_tz,omitempty"`
 }
 
-// internal record with real time.Time for sorting/comparison.
 type rec struct {
 	Hash      string
 	Bytes     int64
@@ -25,30 +22,20 @@ type rec struct {
 	CreatorTZ string
 }
 
-// Index is an in-memory index keyed by hash.
 type Index struct {
 	mu   sync.RWMutex
 	hash map[string]rec
 }
 
-// New creates an empty Index.
-func New() *Index {
-	return &Index{
-		hash: make(map[string]rec),
-	}
-}
+func New() *Index { return &Index{hash: make(map[string]rec)} }
 
-// Put inserts or replaces an entry.
-// e.StoredAt may be RFC3339( Nano ); if empty/invalid we use time.Now().UTC().
 func (ix *Index) Put(e Entry) error {
 	ix.mu.Lock()
 	defer ix.mu.Unlock()
-
 	t := parseWhen(e.StoredAt)
 	if t.IsZero() {
 		t = time.Now().UTC()
 	}
-
 	ix.hash[e.Hash] = rec{
 		Hash:      e.Hash,
 		Bytes:     e.Bytes,
@@ -59,7 +46,6 @@ func (ix *Index) Put(e Entry) error {
 	return nil
 }
 
-// Delete removes an entry by hash (no error if absent).
 func (ix *Index) Delete(hash string) error {
 	ix.mu.Lock()
 	defer ix.mu.Unlock()
@@ -67,19 +53,14 @@ func (ix *Index) Delete(hash string) error {
 	return nil
 }
 
-// List returns entries sorted by StoredAt descending.
 func (ix *Index) List() ([]Entry, error) {
 	ix.mu.RLock()
 	defer ix.mu.RUnlock()
-
 	tmp := make([]rec, 0, len(ix.hash))
 	for _, r := range ix.hash {
 		tmp = append(tmp, r)
 	}
-	sort.Slice(tmp, func(i, j int) bool {
-		return tmp[i].StoredAt.After(tmp[j].StoredAt)
-	})
-
+	sort.Slice(tmp, func(i, j int) bool { return tmp[i].StoredAt.After(tmp[j].StoredAt) })
 	out := make([]Entry, len(tmp))
 	for i, r := range tmp {
 		out[i] = Entry{
@@ -93,7 +74,6 @@ func (ix *Index) List() ([]Entry, error) {
 	return out, nil
 }
 
-// parseWhen tries RFC3339Nano then RFC3339; returns zero time on failure.
 func parseWhen(s string) time.Time {
 	if s == "" {
 		return time.Time{}