chore: move business tooling out of the public library; tidy filestore naming

Keep the public tree project-generic. Business/one-off tools, deployment
and business docs move to the private oo-workspace repo.

Moved to oo-workspace:
- cmd/ooscan, cmd/pdfamount, cmd/kontoblatt, cmd/kontolink
- internal/xlspipe (cutover-portugal workbook) -> oow workbook build
  (drops the --template/--title flags from oo docs put-xlsx)
- deploy/docker-compose.rclone-webdav.yml + docs/rclone-webdav.md
- docs/crm-associations.md

Removed GitHub-era leftovers:
- .github/workflows/release-please.yml, release-please-config.json,
  .release-please-manifest.json (tags are created on Gitea per SemVer)

Naming: the FileStore subsystem is now filestore_*.go (was file_*.go) to
match files_*.go (project Documents). Docs/AGENTS/README updated.

filestore_es.go

@@ -0,0 +1,325 @@
+package onlyoffice
+
+// Elasticsearch backend of the unified file client (epic #34, F3 #37).
+//
+// OnlyOffice full-text search runs on Elasticsearch (index `files_file`, NEST
+// client on the server). The REST endpoint GET /api/2.0/files/@search/{query}
+// only searches file names in the database, so content search needs a direct
+// ES query. The live server is Elasticsearch 7.16.3; the request shape below
+// is plain REST and stays stdlib-only, matching the repo's no-extra-deps rule.
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"regexp"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// The canonical model (Kind, Entry, SearchQuery, SearchHit, Searcher) lives in
+// filestore_core.go (F1 #35).
+
+const (
+	defaultESIndex    = "files_file"
+	defaultESLimit    = 20
+	maxESLimit        = 1000
+	maxESResponseSize = 8 << 20
+)
+
+// ESConfig configures the direct Elasticsearch searcher.
+type ESConfig struct {
+	URL    string // scheme://host:port of the ES HTTP endpoint
+	Index  string // index name, default files_file
+	Tenant string // tenantId filter, empty means all tenants
+}
+
+// ESConfigFromEnv reads ONLYOFFICE_ES_URL, ONLYOFFICE_ES_INDEX (default
+// files_file) and ONLYOFFICE_TENANT. The library never loads dotfiles — the
+// CLI does that.
+func ESConfigFromEnv() ESConfig {
+	return ESConfig{
+		URL:    strings.TrimRight(strings.TrimSpace(os.Getenv("ONLYOFFICE_ES_URL")), "/"),
+		Index:  firstNonEmpty(os.Getenv("ONLYOFFICE_ES_INDEX"), defaultESIndex),
+		Tenant: strings.TrimSpace(os.Getenv("ONLYOFFICE_TENANT")),
+	}
+}
+
+// ESSearcher queries OnlyOffice's Elasticsearch index directly for file name
+// and document content.
+type ESSearcher struct {
+	cfg  ESConfig
+	http *http.Client
+}
+
+// NewESSearcher returns a searcher for the OnlyOffice Elasticsearch index.
+// The URL is required; an empty index falls back to files_file.
+func NewESSearcher(cfg ESConfig) (*ESSearcher, error) {
+	if strings.TrimSpace(cfg.URL) == "" {
+		return nil, fmt.Errorf("onlyoffice: elasticsearch URL is empty (set ONLYOFFICE_ES_URL)")
+	}
+	cfg.URL = strings.TrimRight(cfg.URL, "/")
+	if cfg.Index == "" {
+		cfg.Index = defaultESIndex
+	}
+	return &ESSearcher{cfg: cfg, http: &http.Client{Timeout: 30 * time.Second}}, nil
+}
+
+// Name implements Searcher.
+func (s *ESSearcher) Name() string { return "elasticsearch" }
+
+// Search runs a multi_match over title (and, when q.InContent is set,
+// document.attachment.content), filtered by tenant and optional folder.
+func (s *ESSearcher) Search(ctx context.Context, q SearchQuery) ([]SearchHit, error) {
+	q.Text = strings.TrimSpace(q.Text)
+	if q.Text == "" {
+		return nil, fmt.Errorf("onlyoffice: empty search query")
+	}
+	body, err := json.Marshal(esSearchRequest(q, s.cfg.Tenant))
+	if err != nil {
+		return nil, fmt.Errorf("onlyoffice: build elasticsearch query: %w", err)
+	}
+	endpoint := s.cfg.URL + "/" + s.cfg.Index + "/_search"
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, endpoint, bytes.NewReader(body))
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Accept", "application/json")
+	resp, err := s.http.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("onlyoffice: elasticsearch search: %w", err)
+	}
+	defer resp.Body.Close()
+	raw, err := io.ReadAll(io.LimitReader(resp.Body, maxESResponseSize))
+	if err != nil {
+		return nil, err
+	}
+	if resp.StatusCode >= 400 {
+		return nil, fmt.Errorf("onlyoffice: elasticsearch search: %d %s", resp.StatusCode, truncate(string(raw), 400))
+	}
+	return parseESSearchResponse(raw)
+}
+
+// esSearchRequest builds the ES query body. Pure, so it is unit-tested.
+func esSearchRequest(q SearchQuery, tenant string) esRequest {
+	limit := q.Limit
+	if limit <= 0 {
+		limit = defaultESLimit
+	}
+	if limit > maxESLimit {
+		limit = maxESLimit
+	}
+	fields := []string{"title^2"}
+	if q.InContent {
+		fields = append(fields, "document.attachment.content")
+	}
+	var must []esClause
+	if q.Substring {
+		for _, term := range strings.Fields(strings.ToLower(q.Text)) {
+			if term = escapeWildcard(term); term != "" {
+				must = append(must, esClause{Wildcard: map[string]any{"title": "*" + term + "*"}})
+			}
+		}
+	}
+	if len(must) == 0 {
+		must = []esClause{{MultiMatch: &esMultiMatch{Query: q.Text, Fields: fields}}}
+	}
+
+	var filter []esClause
+	if t := strings.TrimSpace(tenant); t != "" {
+		filter = append(filter, esClause{Term: map[string]any{"tenantId": numericOrString(t)}})
+	}
+	if f := strings.TrimSpace(q.FolderID); f != "" {
+		// folders is an ES nested field; a plain term on folders.folderId would
+		// not match. The stored Folders list holds every ancestor id, so
+		// filtering by a project root id scopes to its whole subtree.
+		filter = append(filter, esClause{Nested: &esNested{
+			Path:  "folders",
+			Query: esNestedTerm{Term: map[string]any{"folders.folderId": f}},
+		}})
+	}
+	for _, ext := range normalizeExtensions(q.Extensions) {
+		filter = append(filter, esClause{Wildcard: map[string]any{"title": "*." + ext}})
+	}
+
+	highlightFields := map[string]struct{}{"title": {}}
+	if q.InContent {
+		highlightFields["document.attachment.content"] = struct{}{}
+	}
+	return esRequest{
+		Size:      limit,
+		Source:    []string{"id", "title", "folders"},
+		Query:     esQuery{Bool: esBool{Must: must, Filter: filter}},
+		Highlight: esHighlight{PreTags: []string{"<em>"}, PostTags: []string{"</em>"}, Fields: highlightFields},
+	}
+}
+
+// normalizeExtensions lowercases, trims leading dots and drops empties.
+func normalizeExtensions(exts []string) []string {
+	out := make([]string, 0, len(exts))
+	seen := map[string]bool{}
+	for _, e := range exts {
+		e = strings.ToLower(strings.TrimSpace(strings.TrimPrefix(strings.TrimSpace(e), ".")))
+		if e == "" || seen[e] {
+			continue
+		}
+		seen[e] = true
+		out = append(out, e)
+	}
+	return out
+}
+
+// numericOrString keeps an integer-looking filter value numeric (tenantId is
+// a long) and leaves anything else as a string (folderId is a text token).
+func numericOrString(s string) any {
+	if n, err := strconv.ParseInt(s, 10, 64); err == nil {
+		return n
+	}
+	return s
+}
+
+// esRequest is the subset of the ES query DSL this client emits.
+type esRequest struct {
+	Size      int         `json:"size"`
+	Source    []string    `json:"_source"`
+	Query     esQuery     `json:"query"`
+	Highlight esHighlight `json:"highlight"`
+}
+
+type esQuery struct {
+	Bool esBool `json:"bool"`
+}
+
+type esBool struct {
+	Must   []esClause `json:"must,omitempty"`
+	Filter []esClause `json:"filter,omitempty"`
+}
+
+type esClause struct {
+	MultiMatch *esMultiMatch  `json:"multi_match,omitempty"`
+	Term       map[string]any `json:"term,omitempty"`
+	Terms      map[string]any `json:"terms,omitempty"`
+	Wildcard   map[string]any `json:"wildcard,omitempty"`
+	Nested     *esNested      `json:"nested,omitempty"`
+}
+
+type esNested struct {
+	Path  string       `json:"path"`
+	Query esNestedTerm `json:"query"`
+}
+
+type esNestedTerm struct {
+	Term map[string]any `json:"term,omitempty"`
+}
+
+// escapeWildcard strips ES wildcard metacharacters from a user term so a query
+// cannot inject wildcard syntax. Pure, so it is unit-tested.
+func escapeWildcard(s string) string {
+	return strings.NewReplacer("*", "", "?", "", `\`, "").Replace(s)
+}
+
+type esMultiMatch struct {
+	Query  string   `json:"query"`
+	Fields []string `json:"fields"`
+}
+
+type esHighlight struct {
+	PreTags  []string            `json:"pre_tags,omitempty"`
+	PostTags []string            `json:"post_tags,omitempty"`
+	Fields   map[string]struct{} `json:"fields"`
+}
+
+// esResponse is the subset of an ES search response we consume.
+type esResponse struct {
+	Took int `json:"took"`
+	Hits struct {
+		Total struct {
+			Value    int    `json:"value"`
+			Relation string `json:"relation"`
+		} `json:"total"`
+		Hits []esResponseHit `json:"hits"`
+	} `json:"hits"`
+}
+
+type esResponseHit struct {
+	ID     string  `json:"_id"`
+	Score  float64 `json:"_score"`
+	Source struct {
+		ID      int    `json:"id"`
+		Title   string `json:"title"`
+		Folders []struct {
+			FolderID string `json:"folderId"`
+			ID       int    `json:"id"`
+		} `json:"folders"`
+	} `json:"_source"`
+	Highlight map[string][]string `json:"highlight"`
+}
+
+// parseESSearchResponse converts an ES search response into SearchHit values.
+// Pure, so it is unit-tested.
+func parseESSearchResponse(raw []byte) ([]SearchHit, error) {
+	var r esResponse
+	if err := json.Unmarshal(raw, &r); err != nil {
+		return nil, fmt.Errorf("onlyoffice: decode elasticsearch response: %w", err)
+	}
+	hits := make([]SearchHit, 0, len(r.Hits.Hits))
+	for _, h := range r.Hits.Hits {
+		id := strconv.Itoa(h.Source.ID)
+		if h.Source.ID == 0 {
+			id = h.ID
+		}
+		// Folders is the ancestor breadcrumb in root → leaf order, so the last
+		// entry is the immediate parent (the previous "first" value was the
+		// project root, which made every result look like it lived in #522).
+		var parent string
+		path := make([]string, 0, len(h.Source.Folders))
+		for _, f := range h.Source.Folders {
+			if strings.TrimSpace(f.FolderID) == "" {
+				continue
+			}
+			path = append(path, f.FolderID)
+		}
+		if len(path) > 0 {
+			parent = path[len(path)-1]
+		}
+		hits = append(hits, SearchHit{
+			Entry: Entry{
+				ID:       id,
+				ParentID: parent,
+				Title:    h.Source.Title,
+				Kind:     File,
+				Provider: "elasticsearch",
+			},
+			Score:     h.Score,
+			Highlight: esHighlightText(h.Highlight),
+			Path:      path,
+		})
+	}
+	return hits, nil
+}
+
+var esHighlightTag = regexp.MustCompile(`</?em[^>]*>`)
+
+// esHighlightText flattens a highlight map into one plain-text snippet,
+// preferring the content fragment over the title. It covers both the
+// OnlyOffice content field and the own-index "content" field.
+func esHighlightText(hl map[string][]string) string {
+	for _, key := range []string{"document.attachment.content", "content", "title"} {
+		frags := hl[key]
+		if len(frags) == 0 {
+			continue
+		}
+		clean := make([]string, 0, len(frags))
+		for _, f := range frags {
+			clean = append(clean, esHighlightTag.ReplaceAllString(f, ""))
+		}
+		return strings.Join(clean, " … ")
+	}
+	return ""
+}