feat: enhance host resolution, filtering, and cache management

- **Strategies**: Add resolver strategy input validation and parsing in setup wizard. Support comma-separated input with known strategy mapping.
- **Client**: Extend Search and SearchAll to include kind and tag filters. Add pagination for full cache refresh handling large datasets.
- **Cache**: Introduce `RecentlyUsed` and `MarkUsed`. Persist `LastUsed` timestamps for entries.
- **TUI**: Add recent hosts view, tag/kind filters, and inline editor for user/port override.
- **Tests**: Comprehensive unit tests for new features, including strategy validation, cache behavior, and client filtering.
- **Docs**: Update README with new TUI features and cache subcommands.

internal/cache/cache.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"os"
 	"path/filepath"
+	"sort"
 	"strings"
 	"sync"
 	"time"
@@ -15,6 +16,7 @@ type Entry struct {
 	Kind     string    `json:"kind"`
 	Tags     []string  `json:"tags,omitempty"`
 	CachedAt time.Time `json:"cached_at"`
+	LastUsed time.Time `json:"last_used,omitempty"`
 }
 
 type Cache struct {
@@ -86,6 +88,39 @@ func (c *Cache) Upsert(e Entry) {
 	c.mu.Unlock()
 }
 
+// MarkUsed records the current time as LastUsed for the named entry.
+// It is a no-op if the entry does not exist.
+func (c *Cache) MarkUsed(name string) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if e, ok := c.entries[name]; ok {
+		e.LastUsed = time.Now()
+		c.entries[name] = e
+	}
+}
+
+// RecentlyUsed returns the n most recently used entries, sorted by LastUsed desc.
+// Entries that have never been used (LastUsed zero) are excluded.
+// If n <= 0, all used entries are returned.
+func (c *Cache) RecentlyUsed(n int) []Entry {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	var used []Entry
+	for _, e := range c.entries {
+		if !e.LastUsed.IsZero() {
+			used = append(used, e)
+		}
+	}
+	sort.Slice(used, func(i, j int) bool {
+		return used[i].LastUsed.After(used[j].LastUsed)
+	})
+	if n > 0 && len(used) > n {
+		used = used[:n]
+	}
+	return used
+}
+
 // Search returns all entries whose name starts with prefix (case-insensitive).
 // TTL is intentionally ignored — this is used for shell completion.
 func (c *Cache) Search(prefix string) []Entry {