docs: improve SEO for quick start guide

[ekline]

Context

This PR addresses an SEO issue identified by auditing the Fastn documentation against the company's keyword strategy derived from fastn.ai.

Keyword map

Type	Keywords
Primary	embedded integration platform, AI agent integrations, adaptive context layer, MCP server, workflow automation
Secondary	tool orchestration, multi-tenant integration, OAuth management, connector platform, AI automation, unified context layer
Audience	SaaS companies, AI agent builders, developers, engineering teams

Top 3 findings

Rank	Priority	Page	Issue	Proposed fix
1	High	flows/quick-start-guide.md	Generic title "Quick Start Guide" contains no product or feature keywords. Description is 86 chars (below 120-char minimum). High-value entry page competing with millions of identical titles.	Rename title to include "Fastn" and "workflow automation". Expand description to ~148 chars with keywords.
2	High	flows/flow-setup-essentials/designing-a-flow/connectors.md (+ 15 sibling pages)	No frontmatter at all — no title, no meta description. Search engines must guess the page topic.	Add frontmatter with description field (120-160 chars) including relevant keywords.
3	Medium	ucl-unified-context-layer/getting-started/about-unified-context-layer/README.md	Description is ~98 chars and doesn't include primary keywords "AI agent", "MCP", or "Fastn".	Expand description to ~150 chars incorporating primary keywords.

What this PR fixes

Issue #1: Quick start guide — generic title and short meta description

• Title: Changed from "Quick Start Guide" to "Fastn quick start: build your first workflow automation"
  • Now includes product name "Fastn" and primary keyword "workflow automation"
  • Differentiates from millions of generic "Quick Start Guide" pages in search results
• Meta description: Expanded from 86 chars to ~148 chars
  • Before: Build a working flow in under 10 minutes. No prior Fastn experience required.
  • After: Build your first Fastn workflow automation in under 10 minutes. Create an API-triggered flow that sends Slack messages, with no prior Fastn experience required.
  • Now includes keywords: "Fastn", "workflow automation", "API-triggered", "flow", "Slack"

Remaining items

• Tutorial: Your first embedded integration widget #2: Add frontmatter to 16+ flow design pages under designing-a-flow/ (connectors, database, data-mapper, variables, switch, loop, etc.)
• Tutorial: Build your first flow #3: Expand UCL "About" page description to include "AI agent", "MCP", and "Fastn" keywords

How to verify

1. Check that the updated frontmatter renders correctly in GitBook
2. Confirm the H1 heading displays properly on the page
3. Preview the page in search results using a SERP preview tool to verify title length (under 60 chars) and description length (120-160 chars)