chore: wire react track into manifests and stack mappings

- agent.yaml: add react-patterns, react-performance, react-testing
  to the skills array; add react-build, react-review, react-test to
  the commands array (alphabetically inserted to satisfy the
  ci/agent-yaml-surface sync test).
- config/project-stack-mappings.json: extend the `react` stack
  entry — add "react" to rules array (was ["common","typescript",
  "web"]); add react-patterns, react-performance, react-testing,
  accessibility to the skills array.
- docs/COMMAND-REGISTRY.json: bump totalCommands 75 -> 78; add
  three new entries (react-build, react-review, react-test) with
  primaryAgents / allAgents / skills wiring. react-review's
  allAgents includes typescript-reviewer to reflect the dual-agent
  routing convention.
- CLAUDE.md: add Skills-table row mapping *.tsx / *.jsx /
  components/** to react-patterns + react-testing skills and
  the /react-review, /react-build, /react-test commands.

config/project-stack-mappings.json

@@ -58,10 +58,14 @@
       "indicators": [
         { "file": "package.json", "contains": "\"react\":" }
       ],
-      "rules": ["common", "typescript", "web"],
+      "rules": ["common", "typescript", "web", "react"],
       "skills": [
         "coding-standards",
         "frontend-patterns",
+        "react-patterns",
+        "react-performance",
+        "react-testing",
+        "accessibility",
         "tdd-workflow",
         "verification-loop"
       ],