chore(ms-ai-architect): align plugin.json and .gitignore with marketplace

Bump version to 1.7.0 (open-source release). Add author full name,
license, repository URL, and keywords to plugin.json.

Modernize .gitignore: remove dead orchestrator/ entries, add .claude/,
node_modules/, *.pdf, *.log, secrets.*.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

plugins/ms-ai-architect/.gitignore

@@ -1,15 +1,22 @@
 *.local.md
-.claude/settings.local.json
 .mcp.json
 .DS_Store
+.claude/
 
 # Secrets
 .env
 *.key
 *.pem
 credentials.*
+secrets.*
 
-orchestrator/state.json
-orchestrator/logs/
+# Generated artifacts
+*.pdf
+*.log
+
+# Node
+node_modules/
+
+# Runtime state
 .work/
 org/