feat: add smart SQL completion with frequency-based sorting

- Add history frequency tracking for SQL keywords
- Store frequency data in ~/.config/pgcli/history_freq.db
- Support runtime toggle via \\set smart_completion_freq on/off
- Default disabled, compatible with existing prompt_toolkit completion

Author: koillinjag-tech

pgcli/main.py

@@ -282,6 +282,7 @@ def __init__(
             "less_chatty": less_chatty,
             "keyword_casing": keyword_casing,
             "alias_map_file": c["main"]["alias_map_file"] or None,
+            "smart_completion_freq": c["main"].as_bool("smart_completion_freq"),
         }
 
         completer = PGCompleter(smart_completion, pgspecial=self.pgspecial, settings=self.settings)

pgcli/packages/history_freq.py

@@ -91,8 +91,23 @@ def record_keyword_usage(self, keyword):
     def record_keywords_batch(self, keywords):
         if not keywords:
             return
+        keyword_counts = defaultdict(int)
         for keyword in keywords:
-            self.record_keyword_usage(keyword)
+            if keyword and isinstance(keyword, str):
+                kw = keyword.upper().strip()
+                if kw:
+                    keyword_counts[kw] += 1
+        if not keyword_counts:
+            return
+        with self._get_cursor() as cursor:
+            for keyword, count in keyword_counts.items():
+                cursor.execute("""
+                    INSERT INTO keyword_frequency (keyword, frequency, last_used)
+                    VALUES (?, ?, CURRENT_TIMESTAMP)
+                    ON CONFLICT(keyword) DO UPDATE SET 
+                        frequency = frequency + ?,
+                        last_used = CURRENT_TIMESTAMP
+                """, (keyword, count, count))
 
     def get_keyword_frequency(self, keyword):
         if not keyword:

pgcli/packages/prioritization.py

@@ -53,9 +53,13 @@ def clear_names(self):
         self.name_counts = defaultdict(int)
 
     def update_keywords(self, text):
+        found_keywords = []
         for keyword, regex in keyword_regexs.items():
             for _ in regex.finditer(text):
                 self.keyword_counts[keyword] += 1
+                found_keywords.append(keyword)
+        if self.smart_completion_freq and self._history_freq_manager and found_keywords:
+            self._history_freq_manager.record_keywords_batch(found_keywords)
 
     def keyword_count(self, keyword):
         session_count = self.keyword_counts[keyword]