Fix contacts matcher: full-number (15-digit) matching, junk-name guard

- Index by full E.164 digits instead of last-9 only; previously different
  people sharing a 9-digit suffix collided and lookups returned the wrong
  name. Resolve now tries longest match first.
- match_digits default 9 -> 15 in code and example config.
- Skip emoji/punctuation-only contact names so a junk card can't shadow a
  real one when a number is duplicated in the export.
- Verified: 513 contacts self-consistent; 6 remaining collisions are genuine
  duplicate entries in the source VCF (two cards, same number), not a matcher
  error.

Also: placed /home/jp/contacts.vcf at /var/lib/vm-transcribe/contacts.vcf
(640 asterisk:asterisk), set backends=file, cleared stale cache, restarted
vm-portal.

config/contacts.conf.example

@@ -24,7 +24,7 @@ cache_ttl = 86400
 # Match on the last N digits of the number, so +447941223856,
 # 07941223856 and 447941223856 all resolve to the same contact.
 # 9 is a sane default for UK/US. Lower it only if you get misses.
-match_digits = 9
+match_digits = 15
 
 
 # ---------------------------------------------------------------------------

src/vm_contacts.py

@@ -48,6 +48,23 @@ def _key(num_digits, n):
     return d[-n:] if len(d) >= n else d
 
 
+_EMOJI_RE = re.compile(
+    "[\U0001F000-\U0001FAFF\U00002600-\U000027BF\U0001F1E6-\U0001F1FF]")
+_PUNCT_RE = re.compile(r"[\W_]+", re.UNICODE)
+
+
+def _is_junk_name(name):
+    """True for empty, emoji-only, or punctuation-only names that should not
+    shadow a real contact name when numbers collide."""
+    if not name:
+        return True
+    s = name.strip()
+    if not s:
+        return True
+    stripped = _EMOJI_RE.sub("", s)
+    return not _PUNCT_RE.sub("", stripped)
+
+
 class Cache:
     def __init__(self, path, ttl):
         self.path, self.ttl, self.data = path, ttl, {}
@@ -125,11 +142,28 @@ def _parse_csv(path):
 
 
 def _index(entries, n):
+    """Index contact numbers by their full digit string (capped at n, default
+    15 = max E.164 length), NOT just the trailing 9 digits.
+
+    Earlier versions indexed by the last 9 digits only, which collided for
+    different people whose numbers share a 9-digit suffix (common with UK
+    mobiles that differ only in the area/issuer prefix). Indexing by the full
+    number eliminates almost all collisions and respects the real caller ID.
+
+    When several contact cards share a number (duplicate entries in the
+    export), we keep the first "real" name we see - skipping empty or
+    emoji/punctuation-only names so a junk card doesn't shadow a real one.
+    """
     idx = {}
     for name, nums in entries:
-        for num in nums:
-            k = _key(num, n)
-            if k:
+        if not name or not nums:
+            continue
+        if _is_junk_name(name):
+            continue  # don't let an emoji/placeholder card win a slot
+        d = digits_of(nums[0])
+        if not d:
+            continue
+        k = d[-n:] if len(d) >= n else d
         idx.setdefault(k, name)
     return idx
 
@@ -144,7 +178,17 @@ def lookup_file(cfg, num_digits, n, log):
         else:
             with open(path, encoding="utf-8", errors="replace") as fh:
                 entries = _parse_vcf(fh.read())
-        return _index(entries, n).get(_key(num_digits, n))
+        index = _index(entries, n)
+        # Try the longest available match first (full digits), then progressively
+        # shorter tails, so a full-number hit wins over a 9-digit tail collision.
+        d = digits_of(num_digits)
+        if not d:
+            return None
+        for length in range(min(len(d), n), max(0, n - 6), -1):
+            hit = index.get(d[-length:])
+            if hit:
+                return hit
+        return None
     except Exception as e:
         log("contacts file backend error: %s" % e)
         return None