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/design-templates/ppt/ib-pitch-book/references/attribution.md

@@ -0,0 +1,35 @@
+# Attribution
+
+This skill adapts the workflow scope of **Pitch Agent** from:
+
+- Repository: [anthropics/financial-services](https://github.com/anthropics/financial-services)
+- Path: `plugins/agent-plugins/pitch-agent/`
+- License: **Apache-2.0**
+
+## What is adapted
+
+- The high-level workflow shape: investment-banking pitch-book generation,
+  strategic-alternatives framing, comps / precedents / DCF / recommendation
+  slide sequence, and the Pitch Agent naming reference.
+- The upstream Apache-2.0 project is credited in `SKILL.md` frontmatter and this
+  notice file.
+
+## What is original to Open Design
+
+- `pattern.html` visual system, fictional NorthPeak / Hartfield content,
+  slide-by-slide copy, tables, styling, and JavaScript.
+- `assets/template.html` seed deck shell and Open Design-specific workflow
+  instructions.
+- The local references in this folder, except where they describe the adapted
+  upstream workflow scope.
+
+## Apache-2.0 notice handling
+
+Retain this attribution file and the upstream link when redistributing or
+modifying the skill. If future edits copy upstream source text, code, prompts,
+or documentation more directly, preserve the upstream Apache-2.0 license notice
+for those adapted portions and document the copied files / sections here.
+
+The Open Design skill bundle (`SKILL.md`, `pattern.html`, `assets/template.html`,
+and references in this folder) is contributed under Open Design's repository
+license except for the adapted workflow ideas noted above.