feat: sqlite persistence with goose migrations, flashcard schema, zap logger

- Add SQLite as authoritative store alongside Qdrant (best-effort indexing)
- Use goose for embedded SQL migrations
- Schema matches flashcard format: id(INTEGER PK), note, repos, host, tags, user, context, created
- Replace std log with zap structured logger
- Split registerTools into registerStoreKnowledge + registerSearchKnowledge
- Qdrant index uses SQLite rowid directly as point ID (no SHA256 hash)
- Search enriches Qdrant results from SQLite by ID
- Lowercase auth header before prefix check
- Always handle json.MarshalIndent errors
- NixOS: StateDirectory, sqlitePath to /var/lib/st-pierre/st-pierre.sqlite

go.mod

@@ -3,20 +3,34 @@ module github.com/didier/st-pierre
 go 1.26.2
 
 require (
-	github.com/google/uuid v1.6.0
 	github.com/mark3labs/mcp-go v0.54.1
+	github.com/pressly/goose/v3 v3.27.1
 	github.com/qdrant/go-client v1.18.2
+	go.uber.org/zap v1.28.0
+	modernc.org/sqlite v1.51.0
 )
 
 require (
+	github.com/dustin/go-humanize v1.0.1 // indirect
 	github.com/google/jsonschema-go v0.4.2 // indirect
+	github.com/google/uuid v1.6.0 // indirect
+	github.com/mattn/go-isatty v0.0.21 // indirect
+	github.com/mfridman/interpolate v0.0.2 // indirect
+	github.com/ncruces/go-strftime v1.0.0 // indirect
+	github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
 	github.com/santhosh-tekuri/jsonschema/v6 v6.0.2 // indirect
+	github.com/sethvargo/go-retry v0.3.0 // indirect
 	github.com/spf13/cast v1.7.1 // indirect
 	github.com/yosida95/uritemplate/v3 v3.0.2 // indirect
+	go.uber.org/multierr v1.11.0 // indirect
 	golang.org/x/net v0.53.0 // indirect
+	golang.org/x/sync v0.20.0 // indirect
 	golang.org/x/sys v0.43.0 // indirect
 	golang.org/x/text v0.36.0 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20260427160629-7cedc36a6bc4 // indirect
 	google.golang.org/grpc v1.80.0 // indirect
 	google.golang.org/protobuf v1.36.11 // indirect
+	modernc.org/libc v1.72.3 // indirect
+	modernc.org/mathutil v1.7.1 // indirect
+	modernc.org/memory v1.11.0 // indirect
 )