docs: replace Story D Pipeline with The Build — PKI from scratch

Story D (The Build): 20 lines of TOML, one command, full PQC PKI.
Shows cat, pki preview, pki build, pki show (root + issuing CA),
pki diff, pki dane — the complete CA-Engine workflow.

Replaces the CI/CD Pipeline story which didn't resonate.

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

Author: rayketcham

README.md

@@ -13,7 +13,7 @@ Pure Rust. No OpenSSL dependency. Human-friendly output. One binary, zero depend
 | [The Audit](https://rayketcham-lab.github.io/PKI-Client/demo.html?demo=audit) | Security auditor reviews expired RSA, hybrid, and PQC certificates |
 | [The Renewal](https://rayketcham-lab.github.io/PKI-Client/demo.html?demo=renewal) | Cron catches an expiring cert — full renewal workflow |
 | [The Migration](https://rayketcham-lab.github.io/PKI-Client/demo.html?demo=migration) | PKI architect presents the RSA → Hybrid → PQC roadmap |
-| [The Pipeline](https://rayketcham-lab.github.io/PKI-Client/demo.html?demo=pipeline) | CI/CD cert validation — automated checks before deploy |
+| [The Build](https://rayketcham-lab.github.io/PKI-Client/demo.html?demo=build) | 20 lines of TOML. One command. Full PQC hierarchy from scratch |
 | [The Handoff](https://rayketcham-lab.github.io/PKI-Client/demo.html?demo=handoff) | Senior engineer onboards a new team member |
 | [The Vision](https://rayketcham-lab.github.io/PKI-Client/demo.html?demo=vision) | From MD5 to 2050 — the past, present, and future of PKI |
 

docs/demo.html

@@ -188,8 +188,8 @@ <h3>PKI-CA-Engine</h3>
     desc: 'Cron job catches an expiring cert. Engineer handles the full renewal workflow.' },
   { key: 'migration', icon: '\uD83D\uDDFA\uFE0F', label: 'The Migration', file: 'demos/story-c-migration.cast',
     desc: 'PKI architect presents the quantum migration roadmap: RSA \u2192 Hybrid \u2192 ML-DSA-87.' },
-  { key: 'pipeline', icon: '\u2699\uFE0F', label: 'The Pipeline', file: 'demos/story-d-pipeline.cast',
-    desc: 'CI/CD certificate validation \u2014 every cert checked and linted before deployment.' },
+  { key: 'build', icon: '\uD83D\uDD28', label: 'The Build', file: 'demos/story-d-build.cast',
+    desc: '20 lines of TOML. One command. Full post-quantum PKI hierarchy from scratch.' },
   { key: 'handoff', icon: '\uD83C\uDF93', label: 'The Handoff', file: 'demos/story-e-handoff.cast',
     desc: 'Senior engineer onboards a new team member: inspect, lint, diff, pin, and probe.' },
   { key: 'vision', icon: '\uD83D\uDE80', label: 'The Vision', file: 'demos/story-f-vision.cast',