docs(portal): add dashboard redesign spec + implementation plan

Spec covers the brainstormed design: jobs-forward layout, V2 stepper
with timestamps, EN Plating teal/gradient palette, 4 doc categories.
Plan decomposes implementation into 4 independently-deployable phases
(tokens+buttons -> dashboard -> jobs detail -> cosmetic sweep) with
27 tasks total.

Also adds .gitignore so .superpowers/ brainstorm artifacts stay
untracked.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

fusion_plating/.gitignore

@@ -0,0 +1,10 @@
+# Superpowers brainstorm session artifacts (mockups, HTML drafts).
+# The companion server saves files here; not project source.
+.superpowers/
+
+# Local Odoo dev artifacts
+*.pyc
+__pycache__/
+*.egg-info/
+.idea/
+.vscode/