refactor!: rename oo-cli → oo, split library by domain, relocate applications

BREAKING:
- Binary renamed oo-cli → oo; install path is now
  github.com/eslider/go-onlyoffice/cmd/oo.
- Former internal/cli tree removed; cobra commands live in cmd/oo/ as
  package main, split by domain (calendar.go, crm.go, tasks.go, apps.go,
  common.go, main.go).
- internal/applications moved to cmd/oo/applications/ (CV-specific workflow;
  not a library feature).
- examples/applications removed (it depended on an internal package).

Library split (mechanical, zero API surface change):
- client.go  — Client, Credentials, Defaults, env helpers, NewClient.
- request.go — Request, Query, Time, Token, MetaResponse, Permissions.
- auth.go    — Authenticate/AuthenticateContext/InvalidateToken.
- http.go    — transport + ResponseArray/ResponseObject/postFormObject/
               putFormObject/deleteObject/unmarshalResponseObject (renamed
               from httpx.go).
- projects.go, tasks.go, users.go, calendar.go, crm.go, files.go — typed
  / untyped domain methods. tasks_extra.go merged into tasks.go.
- onlyoffice.go deleted (content redistributed).

AGENTS.md, CHANGELOG.md, README.md updated accordingly.

Made-with: Cursor

files.go

@@ -2,7 +2,6 @@ package onlyoffice
 
 import (
 	"context"
-	"encoding/json"
 	"fmt"
 	"net/url"
 )
@@ -15,13 +14,5 @@ func (c *Client) UploadOpportunityFile(ctx context.Context, opportunityID, fileP
 	if err != nil {
 		return nil, err
 	}
-	resp, err := responseField(raw, "response")
-	if err != nil {
-		return nil, err
-	}
-	var out map[string]any
-	if err := json.Unmarshal(resp, &out); err != nil {
-		return nil, err
-	}
-	return out, nil
+	return unmarshalResponseObject(raw)
 }