feat: integrate claude-code-base-action as local subaction (#285)

* feat: integrate claude-code-base-action as local subaction

- Copy claude-code-base-action into base-action/ directory
- Update action.yml to reference ./base-action instead of external repo
- Preserve complete base action structure for future refactoring

This eliminates the external dependency while maintaining modularity.

* feat: consolidate CI workflows and add version bump workflow

- Move base-action test workflows to main .github/workflows/
- Update workflow references to use ./base-action
- Add CI jobs for base-action (test, typecheck, prettier)
- Add bump-claude-code-version workflow for base-action
- Remove redundant .github directory from base-action

This consolidates all CI workflows in one place while maintaining
full test coverage for both the main action and base-action.

* tsc

* copy again

* fix tests

* fix: use absolute path for base-action reference

Replace relative path ./base-action with ${{ github.action_path }}/base-action
to ensure the action works correctly when used in other repositories.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

* fix: inline base-action execution to support usage in other repos

Replace uses: ./base-action with direct shell execution since GitHub Actions
doesn't support dynamic paths in composite actions. This ensures the action
works correctly when used in other repositories.

Changes:
- Install Claude Code globally before execution
- Run base-action's index.ts directly with bun
- Pass all required INPUT_* environment variables
- Maintain base-action for future separate publishing

🤖 Generated with [Claude Code](https://claude.ai/code)

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

---------

Co-authored-by: Claude <noreply@anthropic.com>

base-action/src/validate-env.ts

@@ -0,0 +1,54 @@
+/**
+ * Validates the environment variables required for running Claude Code
+ * based on the selected provider (Anthropic API, AWS Bedrock, or Google Vertex AI)
+ */
+export function validateEnvironmentVariables() {
+  const useBedrock = process.env.CLAUDE_CODE_USE_BEDROCK === "1";
+  const useVertex = process.env.CLAUDE_CODE_USE_VERTEX === "1";
+  const anthropicApiKey = process.env.ANTHROPIC_API_KEY;
+  const claudeCodeOAuthToken = process.env.CLAUDE_CODE_OAUTH_TOKEN;
+
+  const errors: string[] = [];
+
+  if (useBedrock && useVertex) {
+    errors.push(
+      "Cannot use both Bedrock and Vertex AI simultaneously. Please set only one provider.",
+    );
+  }
+
+  if (!useBedrock && !useVertex) {
+    if (!anthropicApiKey && !claudeCodeOAuthToken) {
+      errors.push(
+        "Either ANTHROPIC_API_KEY or CLAUDE_CODE_OAUTH_TOKEN is required when using direct Anthropic API.",
+      );
+    }
+  } else if (useBedrock) {
+    const requiredBedrockVars = {
+      AWS_REGION: process.env.AWS_REGION,
+      AWS_ACCESS_KEY_ID: process.env.AWS_ACCESS_KEY_ID,
+      AWS_SECRET_ACCESS_KEY: process.env.AWS_SECRET_ACCESS_KEY,
+    };
+
+    Object.entries(requiredBedrockVars).forEach(([key, value]) => {
+      if (!value) {
+        errors.push(`${key} is required when using AWS Bedrock.`);
+      }
+    });
+  } else if (useVertex) {
+    const requiredVertexVars = {
+      ANTHROPIC_VERTEX_PROJECT_ID: process.env.ANTHROPIC_VERTEX_PROJECT_ID,
+      CLOUD_ML_REGION: process.env.CLOUD_ML_REGION,
+    };
+
+    Object.entries(requiredVertexVars).forEach(([key, value]) => {
+      if (!value) {
+        errors.push(`${key} is required when using Google Vertex AI.`);
+      }
+    });
+  }
+
+  if (errors.length > 0) {
+    const errorMessage = `Environment variable validation failed:\n${errors.map((e) => `  - ${e}`).join("\n")}`;
+    throw new Error(errorMessage);
+  }
+}