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/prepare-prompt.ts

@@ -0,0 +1,82 @@
+import { existsSync, statSync } from "fs";
+import { mkdir, writeFile } from "fs/promises";
+
+export type PreparePromptInput = {
+  prompt: string;
+  promptFile: string;
+};
+
+export type PreparePromptConfig = {
+  type: "file" | "inline";
+  path: string;
+};
+
+async function validateAndPreparePrompt(
+  input: PreparePromptInput,
+): Promise<PreparePromptConfig> {
+  // Validate inputs
+  if (!input.prompt && !input.promptFile) {
+    throw new Error(
+      "Neither 'prompt' nor 'prompt_file' was provided. At least one is required.",
+    );
+  }
+
+  if (input.prompt && input.promptFile) {
+    throw new Error(
+      "Both 'prompt' and 'prompt_file' were provided. Please specify only one.",
+    );
+  }
+
+  // Handle prompt file
+  if (input.promptFile) {
+    if (!existsSync(input.promptFile)) {
+      throw new Error(`Prompt file '${input.promptFile}' does not exist.`);
+    }
+
+    // Validate that the file is not empty
+    const stats = statSync(input.promptFile);
+    if (stats.size === 0) {
+      throw new Error(
+        "Prompt file is empty. Please provide a non-empty prompt.",
+      );
+    }
+
+    return {
+      type: "file",
+      path: input.promptFile,
+    };
+  }
+
+  // Handle inline prompt
+  if (!input.prompt || input.prompt.trim().length === 0) {
+    throw new Error("Prompt is empty. Please provide a non-empty prompt.");
+  }
+
+  const inlinePath = "/tmp/claude-action/prompt.txt";
+  return {
+    type: "inline",
+    path: inlinePath,
+  };
+}
+
+async function createTemporaryPromptFile(
+  prompt: string,
+  promptPath: string,
+): Promise<void> {
+  // Create the directory path
+  const dirPath = promptPath.substring(0, promptPath.lastIndexOf("/"));
+  await mkdir(dirPath, { recursive: true });
+  await writeFile(promptPath, prompt);
+}
+
+export async function preparePrompt(
+  input: PreparePromptInput,
+): Promise<PreparePromptConfig> {
+  const config = await validateAndPreparePrompt(input);
+
+  if (config.type === "inline") {
+    await createTemporaryPromptFile(input.prompt, config.path);
+  }
+
+  return config;
+}