Add rejection retry flow with configurable wait days

- Backend: DELETE /professionals/me resets rejected state so user can retry
- Backend: findRejected/findPending now filter by pro_state
- Admin settings: rejection_wait_days field (default 7)

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

backend/src/professionals/professionals.controller.ts

@@ -1,4 +1,4 @@
-import { Controller, Get, Post, Patch, Param, Body, UseGuards, Req, HttpCode, HttpStatus, NotFoundException } from '@nestjs/common';
+import { Controller, Get, Post, Patch, Delete, Param, Body, UseGuards, Req, HttpCode, HttpStatus, NotFoundException } from '@nestjs/common';
 import { ApiTags, ApiBearerAuth } from '@nestjs/swagger';
 import { ProfessionalsService } from './professionals.service';
 import { JwtAuthGuard } from '../auth/jwt-auth.guard';
@@ -76,6 +76,13 @@ export class ProfessionalsController {
     return this.pros.requestProfessional(req.user.sub, dto);
   }
 
+  @Delete('me')
+  @UseGuards(JwtAuthGuard)
+  @ApiBearerAuth()
+  async deleteMe(@Req() req) {
+    return this.pros.resetRejected(req.user.sub);
+  }
+
   @Patch('me/schedules')
   @UseGuards(JwtAuthGuard)
   @ApiBearerAuth()