Add BMAD planning artifacts: brief, PRD, architecture, UX, spec, tickets

Includes the BMAD install config, the initiative ticket tree, the portal
context-resources scripts, and the .gitignore change that tracks BMAD files
(generated _bmad/render/ is ignored).

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Sk72AxLwQnYttF6VFSxQLt

.gitignore

@@ -13,9 +13,12 @@
 *.vsix
 
 # BMAD method
-.bmad-core/**
-_bmad/**
-_bmad-output/**
-web-bundles/**
-.memlog.md
-_bmad/custom/*.user.toml
+# .bmad-core/**
+# _bmad/**
+# _bmad-output/**
+# web-bundles/**
+# .memlog.md
+# _bmad/custom/*.user.toml
+
+# BMAD generated render cache
+_bmad/render/