homelab v0.8.2: fix memory recall truncating multibyte UTF-8 mid-character

emo's Claude Code sessions hit "UserPromptSubmit hook error" on almost every
prompt. Root cause: the homelab-memory-recall.py UserPromptSubmit hook runs
`homelab memory recall <prompt>` and strict-decodes its stdout. printMemories
truncated each memory's preview with a BYTE slice (c[:240]), which cuts through
the middle of a 2-byte Cyrillic character and emits invalid UTF-8 (a dangling
0xd0 lead byte). The hook's subprocess.run(text=True) then raised
UnicodeDecodeError — not caught by its `except (TimeoutExpired, OSError)` — so
the hook exited non-zero and Claude surfaced the error. It is Cyrillic-specific
(ASCII has no multibyte chars to split), so it bit emo (Bulgarian prompts) every
turn while English users almost never saw it.

Two-layer fix:
- cli: truncatePreview() now counts RUNES, not bytes, so the preview never
  splits a character. Regression test asserts valid UTF-8 on a long Cyrillic
  string. Fixes the root for every consumer of `memory recall` / `memory list`.
- hook: subprocess.run gains errors="replace" and the except is broadened to
  honor the script's own "best-effort, exit 0" contract — so a truncated or
  otherwise odd payload can never again surface as a hook error.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

cli/cmd_memory.go

@@ -54,10 +54,7 @@ func printMemories(raw []byte, jsonOut bool) error {
 		return nil
 	}
 	for _, m := range r.Memories {
-		c := strings.ReplaceAll(m.Content, "\n", " ")
-		if len(c) > 240 {
-			c = c[:240] + "…"
-		}
+		c := truncatePreview(strings.ReplaceAll(m.Content, "\n", " "), 240)
 		fmt.Printf("#%d [%s] (%.2f) %s\n", m.ID, m.Category, m.Importance, c)
 		if m.Tags != "" {
 			fmt.Printf("       tags: %s\n", m.Tags)
@@ -66,6 +63,21 @@ func printMemories(raw []byte, jsonOut bool) error {
 	return nil
 }
 
+// truncatePreview shortens s to at most maxRunes RUNES, appending "…" when it
+// trims. Counting runes (not bytes) is load-bearing: a byte slice like s[:240]
+// can cut through the middle of a multibyte UTF-8 character (e.g. 2-byte
+// Cyrillic), leaving a dangling lead byte = invalid UTF-8. That crashed strict
+// decoders downstream — notably the homelab-memory-recall.py UserPromptSubmit
+// hook (subprocess text=True), which surfaced as a recurring "UserPromptSubmit
+// hook error" for Cyrillic-language users.
+func truncatePreview(s string, maxRunes int) string {
+	r := []rune(s)
+	if len(r) <= maxRunes {
+		return s
+	}
+	return string(r[:maxRunes]) + "…"
+}
+
 func memoryRecall(args []string) error {
 	req := memRecallReq{}
 	jsonOut := false