scripts: use capnp store instead of reading markdown directly

Add store_helpers.py with shared helpers that call poc-memory commands
(list-keys, render, journal-tail) instead of globbing ~/.claude/memory/*.md
and parsing section headers.

All 9 Python scripts updated: get_semantic_keys(), get_topic_file_index(),
get_recent_journal(), parse_journal_entries(), read_journal_range(),
collect_topic_stems(), and file preview rendering now go through the store.

This completes the clean switch — no script reads archived markdown files.

scripts/daily-digest.py

@@ -23,7 +23,6 @@ from datetime import date, datetime
 from pathlib import Path
 
 MEMORY_DIR = Path.home() / ".claude" / "memory"
-JOURNAL = MEMORY_DIR / "journal.md"
 EPISODIC_DIR = MEMORY_DIR / "episodic"
 AGENT_RESULTS_DIR = MEMORY_DIR / "agent-results"
 
@@ -31,41 +30,9 @@ EPISODIC_DIR.mkdir(parents=True, exist_ok=True)
 
 
 def parse_journal_entries(target_date: str) -> list[dict]:
-    """Extract all journal entries for a given date (YYYY-MM-DD)."""
-    entries = []
-    current = None
-
-    with open(JOURNAL) as f:
-        for line in f:
-            # Match entry header: ## 2026-02-28T19:42
-            m = re.match(r'^## (\d{4}-\d{2}-\d{2})T(\d{2}:\d{2})', line)
-            if m:
-                if current is not None:
-                    entries.append(current)
-                entry_date = m.group(1)
-                entry_time = m.group(2)
-                current = {
-                    "date": entry_date,
-                    "time": entry_time,
-                    "timestamp": f"{entry_date}T{entry_time}",
-                    "source_ref": None,
-                    "text": "",
-                }
-                continue
-
-            if current is not None:
-                # Check for source comment
-                sm = re.match(r'<!-- source: (.+?) -->', line)
-                if sm:
-                    current["source_ref"] = sm.group(1)
-                    continue
-                current["text"] += line
-
-    if current is not None:
-        entries.append(current)
-
-    # Filter to target date
-    return [e for e in entries if e["date"] == target_date]
+    """Get journal entries for a given date from the store."""
+    from store_helpers import get_journal_entries_by_date
+    return get_journal_entries_by_date(target_date)
 
 
 def load_agent_results(target_date: str) -> list[dict]:
@@ -90,24 +57,9 @@ def load_agent_results(target_date: str) -> list[dict]:
 
 
 def get_semantic_keys() -> list[str]:
-    """Get all semantic memory file keys."""
-    keys = []
-    for md in sorted(MEMORY_DIR.glob("*.md")):
-        name = md.name
-        if name in ("journal.md", "work-queue.md", "MEMORY.md"):
-            continue
-        keys.append(name)
-        try:
-            with open(md) as f:
-                for line in f:
-                    if line.startswith("## "):
-                        slug = re.sub(r'[^a-z0-9-]', '',
-                                      line[3:].strip().lower().replace(' ', '-'))
-                        if slug:
-                            keys.append(f"{name}#{slug}")
-        except Exception:
-            pass
-    return keys
+    """Get semantic memory keys from the store."""
+    from store_helpers import get_semantic_keys as _get_keys
+    return _get_keys()
 
 
 def build_digest_prompt(target_date: str, entries: list[dict],