stage-10: memory search with Ollama embeddings + SQLite

Semantic search over memory/*.md files using all-minilm embeddings.
Adds /search Discord command and `echo memory search/reindex` CLI.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/adapters/discord_bot.py

@@ -124,6 +124,7 @@ def create_bot(config: Config) -> discord.Client:
             "`/logs [n]` — Show last N log lines (default 10)",
             "`/restart` — Restart the bot process (owner only)",
             "`/heartbeat` — Run heartbeat health checks",
+            "`/search <query>` — Search Echo's memory",
             "",
             "**Cron Jobs**",
             "`/cron list` — List all scheduled jobs",
@@ -413,6 +414,41 @@ def create_bot(config: Config) -> discord.Client:
                 f"Heartbeat error: {e}", ephemeral=True
             )
 
+    @tree.command(name="search", description="Search Echo's memory")
+    @app_commands.describe(query="What to search for")
+    async def search_cmd(
+        interaction: discord.Interaction, query: str
+    ) -> None:
+        await interaction.response.defer()
+        try:
+            from src.memory_search import search
+
+            results = await asyncio.to_thread(search, query)
+            if not results:
+                await interaction.followup.send(
+                    "No results found (index may be empty — run `echo memory reindex`)."
+                )
+                return
+
+            lines = [f"**Search results for:** {query}\n"]
+            for i, r in enumerate(results, 1):
+                score = r["score"]
+                preview = r["chunk"][:150]
+                if len(r["chunk"]) > 150:
+                    preview += "..."
+                lines.append(
+                    f"**{i}.** `{r['file']}` (score: {score:.3f})\n{preview}\n"
+                )
+            text = "\n".join(lines)
+            if len(text) > 1900:
+                text = text[:1900] + "\n..."
+            await interaction.followup.send(text)
+        except ConnectionError as e:
+            await interaction.followup.send(f"Search error: {e}")
+        except Exception as e:
+            logger.exception("Search command failed")
+            await interaction.followup.send(f"Search error: {e}")
+
     @tree.command(name="channels", description="List registered channels")
     async def channels(interaction: discord.Interaction) -> None:
         ch_map = config.get("channels", {})