Bootstrap agent-ready docs and permissions (D-036)

Root AGENTS.md is now the single source of truth for coding agents;
CLAUDE.md, GEMINI.md and docs/CLAUDE.md are pointers. The product spec
moves from docs/CLAUDE.md to PRODUCT.md, DESIGN.md records the shipped
visual system, and docs/PERMISSIONS.md defines agent permission tiers
rendered to .claude/, .codex/ and .gemini/. Adds docs/specs/ and
docs/plans/, logs issues noticed (not fixed) in WorkBreakdown.md.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.gemini/settings.json

@@ -0,0 +1,20 @@
+{
+  "tools": {
+    "allowed": [
+      "run_shell_command(git status)", "run_shell_command(git diff)", "run_shell_command(git log)",
+      "run_shell_command(git show)", "run_shell_command(git branch --list)",
+      "run_shell_command(git rev-parse)", "run_shell_command(git add)", "run_shell_command(git commit)",
+      "run_shell_command(bun install --frozen-lockfile)", "run_shell_command(bun test)",
+      "run_shell_command(bun run build)", "run_shell_command(bun run icons)", "run_shell_command(bun dev)"
+    ],
+    "exclude": [
+      "run_shell_command(git push --force)", "run_shell_command(git push -f)",
+      "run_shell_command(git push --force-with-lease)", "run_shell_command(git reset --hard)",
+      "run_shell_command(git clean)", "run_shell_command(git add -f)", "run_shell_command(git add --force)",
+      "run_shell_command(git commit --no-verify)", "run_shell_command(git commit -n)",
+      "run_shell_command(rm -r)", "run_shell_command(rm -R)", "run_shell_command(rm -rf)",
+      "run_shell_command(rm -fr)", "run_shell_command(rm -Rf)", "run_shell_command(rm -fR)",
+      "run_shell_command(rm --recursive)", "run_shell_command(sudo)"
+    ]
+  }
+}