feat: IMAP mail sync with thread-to-contact matching (PRD §6.1)

Real IMAP connection via imapflow library:
- Connects to IMAP server (IMAPFlow, TLS on port 993)
- Fetches recent messages (configurable limit, default 20)
- Extracts: from, fromEmail, subject, date, snippet (200 chars)
- Thread-to-contact matching (PRD §6.1):
  1. Match sender email against persons table
  2. If no person match, extract domain and match against company.website
  3. Returns matchedCompany + matchedPerson for each email
- Audit-logged (action: crm.mailsync:imap)
- Zod validated (host, port, user, password, folder, limit)
- 502 on IMAP connection failure with detail
- 400 on validation failure

Tested: invalid creds → 502 'IMAP connection failed', missing host → 400

skills/design/horizontal-craft/README.md

@@ -0,0 +1,92 @@
+# Horizontal Craft
+
+Horizontal craft files are cross-cutting design constraints. They are not artifact skills, templates, or scenario principles.
+
+Use them after a lightweight design understanding step has determined what the artifact needs. Do not read every file by default.
+
+```yaml
+skill_bundle:
+  horizontal_craft:
+    # Always for Chinese artifacts
+    - horizontal-craft/chinese-typography.md
+
+    # Generative craft, loaded when needed
+    - horizontal-craft/color.md
+    - horizontal-craft/icon-system.md
+    - horizontal-craft/animation-discipline.md
+    - horizontal-craft/laws-of-ux.md
+    - horizontal-craft/technique-library.md
+
+    # Guardrail craft, usually applied during review or when triggered
+    - horizontal-craft/anti-ai-slop.md
+    - horizontal-craft/accessibility.md
+    - horizontal-craft/state-coverage.md
+    - horizontal-craft/form-validation.md
+    - horizontal-craft/data-integrity.md
+    - horizontal-craft/link-and-proof.md
+```
+
+`quality-gate.md` verifies whether the relevant horizontal craft checks passed. It should not duplicate the full rulebooks.
+
+## Loading Priority
+
+Do not read every horizontal craft file by default. Load only what the task needs.
+
+### Baseline for Chinese visual design
+
+- Read `chinese-typography.md` whenever the artifact contains meaningful Chinese text.
+- Read `reference/fonts.md` when font choice materially affects the visual direction: font-related user requests, typography-led covers/posters/cards/deck covers, official documents, classical/literary content, academic/report tone, industrial/technology display type, or when title/body font attitudes must differ.
+- Do not read `reference/fonts.md` for every Chinese task; for ordinary Web/App/Dashboard output without font intent, use a safe system font stack.
+- Read other deep files in `reference/` only when their trigger conditions apply.
+
+### Generative craft
+
+Read these before or during drafting when their trigger applies:
+
+- `color.md` — read when no strong design system is provided, when color direction is vague, when semantic colors/status colors are used, or when the artifact risks default blue-purple gradient styling.
+- `chinese-typography.md` — read for all Chinese-language artifacts.
+  It provides principles and diagnostics, not a universal type-scale preset; concrete sizes should come from the artifact skill, template, design system, or canvas/device registry.
+- `icon-system.md` — read when the artifact uses icons, pictograms, status marks, or icon-like decoration.
+- `animation-discipline.md` — read when motion, transitions, scroll reveal, microinteractions, or animated H5 behavior are requested or implied.
+- `laws-of-ux.md` — read for decision-heavy or interaction-heavy surfaces such as pricing pages, onboarding, dashboards, forms, H5 tools, and product flows.
+- `technique-library.md` — read only for advanced front-end effects such as GSAP, Three.js, shaders, rich motion, or data visualization technique selection.
+
+### Guardrail craft
+
+Usually apply these during review, or earlier only when the task clearly triggers them:
+
+- `anti-ai-slop.md` — use as an anti-default check, not as the primary creative direction.
+- `accessibility.md` — apply as a final baseline check for web artifacts.
+- `state-coverage.md` — read for interactive, data-driven, form, tool, dashboard, or prototype surfaces.
+- `form-validation.md` — read for signup, login, checkout, calculators, input-heavy H5, settings, admin forms, or any artifact with validation/error messaging.
+- `data-integrity.md` — read when charts, metrics, benchmarks, forecasts, calculations, or proof-like numbers appear.
+- `link-and-proof.md` — read when links, CTAs, customer proof, testimonials, logos, awards, or external claims appear.
+
+### Removed boundary
+
+There is no standalone `chinese-copy.md`. Copywriting is not a core design craft. Only short copy-related failure smells that visibly affect design quality remain in `anti-ai-slop.md`.
+
+## Boundary with Scenario Principles and Templates
+
+Templates live outside horizontal craft in `templates/`. They provide optional concrete structure seeds.
+
+Scenario principles decide business priorities. Horizontal craft decides cross-cutting execution quality.
+
+Horizontal craft files are universal constraints that can apply to any scenario or template. `technique-library.md` is here because advanced front-end technique selection is a cross-cutting implementation rule, not an artifact skill.
+
+## Reference Loading Rule
+
+Deep reference files are not passive appendices. When a selected horizontal craft file contains a clear trigger condition, add the matching reference file to `required_reference_files_to_read`. Do not rely on the summary file alone for typography-heavy, publication, report, fixed-image, or punctuation-sensitive work.
+
+For normal UI work, read only the top-level craft file. For typography-heavy work, read 1–3 relevant files from `horizontal-craft/reference/`.
+
+## Deep Reference Files
+
+`reference/` lives inside `horizontal-craft/` because these files are deep typography and layout references used primarily by `chinese-typography.md`. Keep them here instead of the design root.
+
+- `reference/directions.md`
+- `reference/title-and-breaking.md`
+- `reference/punctuation.md`
+- `reference/grid-system.md`
+- `reference/text-detail.md`
+- `reference/fonts.md`