docs: initialize Umzugsliste roadmap (7 phases)

WordPress plugin for digital moving list form with legacy email format preservation.

Phases:
1. Foundation: Plugin infrastructure, CPT, admin menu
2. Legacy Data Extraction: Extract furniture data from legacy PHP
3. Settings System: Admin settings with email and captcha config
4. Form Rendering: Shortcode and form frontend matching legacy
5. Volume Calculations: cbm calculations matching legacy logic
6. Email System: Legacy HTML table format and wp_mail()
7. Captcha & Validation: reCAPTCHA v2/v3, hCaptcha, i18n

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

.planning/ROADMAP.md

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+# Roadmap: Umzugsliste
+
+## Overview
+
+Transform the legacy standalone moving list form into a secure, integrated WordPress plugin. The journey starts with plugin foundation and data extraction, builds the form frontend with exact volume calculations, implements the critical legacy email format, and finishes with captcha protection and validation. Each phase delivers a verifiable piece of functionality while preserving the exact email format that office staff depend on.
+
+## Domain Expertise
+
+None
+
+## Phases
+
+- [ ] **Phase 1: Foundation** - Plugin infrastructure, CPT, admin menu
+- [ ] **Phase 2: Legacy Data Extraction** - Extract furniture data from legacy PHP files
+- [ ] **Phase 3: Settings System** - Admin settings page with email and captcha config
+- [ ] **Phase 4: Form Rendering** - Shortcode and form frontend matching legacy structure
+- [ ] **Phase 5: Volume Calculations** - cbm calculations matching legacy logic exactly
+- [ ] **Phase 6: Email System** - Legacy HTML table format generation and wp_mail() integration
+- [ ] **Phase 7: Captcha & Validation** - reCAPTCHA v2/v3, hCaptcha, inline validation, i18n
+
+## Phase Details
+
+### Phase 1: Foundation
+**Goal**: Core plugin structure with CPT for storing submissions and admin menu
+**Depends on**: Nothing (first phase)
+**Research**: Unlikely (standard WordPress plugin patterns)
+**Plans**: TBD
+
+Plans:
+- [ ] TBD during phase planning
+
+### Phase 2: Legacy Data Extraction
+**Goal**: Extract all furniture items, room definitions, and cbm values from legacy PHP into structured arrays
+**Depends on**: Phase 1
+**Research**: Unlikely (internal work extracting PHP arrays)
+**Plans**: TBD
+
+Plans:
+- [ ] TBD during phase planning
+
+### Phase 3: Settings System
+**Goal**: Admin settings page with receiver email, captcha provider selection, thank you URL configuration
+**Depends on**: Phase 1
+**Research**: Unlikely (WordPress Settings API is established)
+**Plans**: TBD
+
+Plans:
+- [ ] TBD during phase planning
+
+### Phase 4: Form Rendering
+**Goal**: Shortcode `[umzugsliste]` renders complete form matching legacy structure (7 room sections)
+**Depends on**: Phase 2, Phase 3
+**Research**: Unlikely (internal HTML generation matching legacy)
+**Plans**: TBD
+
+Plans:
+- [ ] TBD during phase planning
+
+### Phase 5: Volume Calculations
+**Goal**: JavaScript cbm calculations matching legacy logic exactly, real-time total updates
+**Depends on**: Phase 4
+**Research**: Unlikely (porting existing logic)
+**Plans**: TBD
+
+Plans:
+- [ ] TBD during phase planning
+
+### Phase 6: Email System
+**Goal**: Generate legacy HTML table format email and send via wp_mail() with CPT storage before sending
+**Depends on**: Phase 4, Phase 5
+**Research**: Unlikely (wp_mail() is standard WordPress)
+**Plans**: TBD
+
+Plans:
+- [ ] TBD during phase planning
+
+### Phase 7: Captcha & Validation
+**Goal**: Integrate reCAPTCHA v2/v3 and hCaptcha, inline form validation, German/English i18n
+**Depends on**: Phase 6
+**Research**: Likely (external APIs)
+**Research topics**: Current reCAPTCHA v2 API, reCAPTCHA v3 API, hCaptcha integration patterns, WordPress i18n best practices
+**Plans**: TBD
+
+Plans:
+- [ ] TBD during phase planning
+
+## Progress
+
+| Phase | Plans Complete | Status | Completed |
+|-------|----------------|--------|-----------|
+| 1. Foundation | 0/TBD | Not started | - |
+| 2. Legacy Data Extraction | 0/TBD | Not started | - |
+| 3. Settings System | 0/TBD | Not started | - |
+| 4. Form Rendering | 0/TBD | Not started | - |
+| 5. Volume Calculations | 0/TBD | Not started | - |
+| 6. Email System | 0/TBD | Not started | - |
+| 7. Captcha & Validation | 0/TBD | Not started | - |

.planning/STATE.md

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+# Project State
+
+## Project Reference
+
+See: .planning/PROJECT.md (updated 2026-01-16)
+
+**Core value:** Email format identical to legacy — office staff workflow depends on the exact HTML table structure.
+**Current focus:** Phase 1 — Foundation
+
+## Current Position
+
+Phase: 1 of 7 (Foundation)
+Plan: Not started
+Status: Ready to plan
+Last activity: 2026-01-16 — Roadmap created
+
+Progress: ░░░░░░░░░░ 0%
+
+## Performance Metrics
+
+**Velocity:**
+- Total plans completed: 0
+- Average duration: —
+- Total execution time: 0 hours
+
+**By Phase:**
+
+| Phase | Plans | Total | Avg/Plan |
+|-------|-------|-------|----------|
+| — | — | — | — |
+
+**Recent Trend:**
+- Last 5 plans: —
+- Trend: —
+
+## Accumulated Context
+
+### Decisions
+
+Decisions are logged in PROJECT.md Key Decisions table.
+Recent decisions affecting current work:
+
+(None yet)
+
+### Deferred Issues
+
+None yet.
+
+### Blockers/Concerns
+
+None yet.
+
+## Session Continuity
+
+Last session: 2026-01-16 10:55
+Stopped at: Roadmap creation complete
+Resume file: None