test: add Vercel (option 11) to Step 5 walkthrough

The walkthrough table stopped at option 10 (Google Drive) even though
step-5-install.sh ships option 11 (Vercel). Update the Step 5 section:
- Count 10 → 11 optional MCPs
- Interactive menu description: 1-10 → 1-11, add Vercel to list
- Add (11) Vercel row with exact registration command and INSTALLED_VERCEL note
- Fix Notes paragraph: Playwright was incorrectly described as the only
  no-credential-prompt MCP; Vercel also requires no local credentials

Author: fidgetcoding

tests/install-flow-walkthrough.md

@@ -77,12 +77,12 @@ The `OBSIDIAN/` prefix requirement has been removed. The script first reads the
 
 **File:** `step-5/step-5-install.sh`
 
-Installs 10 optional productivity MCPs. Obsidian MCP has moved to [2ndBrain-mogging](https://github.com/lorecraft-io/2ndBrain-mogging), NOT here.
+Installs 11 optional productivity MCPs. Obsidian MCP has moved to [2ndBrain-mogging](https://github.com/lorecraft-io/2ndBrain-mogging), NOT here.
 
 | Section | Expected Behavior | Result |
 |---------|-------------------|--------|
 | Non-interactive mode | Detects pipe (`[ ! -t 0 ]`), auto-detects already-installed MCPs, re-enters only the `"already installed"` guards; if nothing found, prints "run directly" instructions and exits cleanly | PASS |
-| Interactive menu | Numbered 1-10: Notion, Granola, n8n, GCal, Morgen, Motion, Playwright, SwiftKit, Superhuman, Google Drive. Morgen (5) flagged as recommended default | PASS |
+| Interactive menu | Numbered 1-11: Notion, Granola, n8n, GCal, Morgen, Motion, Playwright, SwiftKit, Superhuman, Google Drive, Vercel. Morgen (5) flagged as recommended default | PASS |
 | (1) Notion | Prompts for integration token, registers via `-e NOTION_TOKEN=...` | PASS |
 | (2) Granola | Registers HTTP transport to `https://mcp.granola.ai/mcp` (no credentials — Granola app handles auth) | PASS |
 | (3) n8n | Prompts for user's own n8n instance URL + optional Bearer token, registers via `--transport http` with `-H "Authorization: Bearer …"` if provided | PASS |
@@ -93,11 +93,12 @@ Installs 10 optional productivity MCPs. Obsidian MCP has moved to [2ndBrain-mogg
 | (8) SwiftKit | Prompts for API key, registers hosted SwiftKit MCP. | PASS |
 | (9) Superhuman | No local credentials — one-time browser OAuth on first use. | PASS |
 | (10) Google Drive | No local credentials — one-time browser OAuth on first use via Google's hosted MCP. | PASS |
+| (11) Vercel | No local credentials — registers official remote MCP via `claude mcp add --scope user --transport sse vercel https://mcp.vercel.com/sse`. One-time browser OAuth on first use against the user's Vercel account. `INSTALLED_VERCEL` tracker set on success. | PASS |
 | Obsidian | NOT in this repo — see 2ndBrain-mogging | N/A |
 | Self-test | `check_registered` covers all tools, verifies Motion + GCal `.env` files exist for their respective installs | PASS |
 | Summary | Prints tool-count + "what you can do now" hints per installed tool | PASS |
 
-**Notes:** When run via `update.sh` (pipe), correctly auto-detects already-registered MCPs and exits after verification without prompting. First-time users must run directly in terminal for credential input. Morgen is promoted as the default calendar+task tool; Motion and Google Calendar are documented as secondary (install only for specific features the primary tool doesn't cover). Playwright is the only MCP in Step 5 with no credential prompts — it registers directly and downloads its own browser binaries on first use.
+**Notes:** When run via `update.sh` (pipe), correctly auto-detects already-registered MCPs and exits after verification without prompting. First-time users must run directly in terminal for credential input. Morgen is promoted as the default calendar+task tool; Motion and Google Calendar are documented as secondary (install only for specific features the primary tool doesn't cover). Playwright and Vercel are the two MCPs in Step 5 with no local credential prompts — Playwright registers directly and downloads its own browser binaries on first use; Vercel registers the official remote MCP and opens a browser for one-time OAuth on first use.
 
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