feat: add flexible bot access control with allowed_bots option (#117)

* feat: skip permission check for GitHub App bot users

GitHub Apps (users ending with [bot]) now bypass permission checks
as they have their own authorization mechanism.

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

* feat: add allow_bot_users option to control bot user access

- Add allow_bot_users input parameter (default: false)
- Modify checkHumanActor to optionally allow bot users
- Add comprehensive tests for bot user handling
- Improve security by blocking bot users by default

This change prevents potential prompt injection attacks from bot users
while providing flexibility for trusted bot integrations.

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

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

* docs: mark bot user support feature as completed in roadmap

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

* refactor: move allowedBots parameter to context object

Move allowedBots from function parameter to context.inputs to maintain
consistency with other input handling throughout the codebase.

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

* docs: update README for bot user support feature

Add documentation for the new allowed_bots parameter that enables
bot users to trigger Claude actions with granular control.

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

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

* fix: add missing allowedBots property in permissions test

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

* fix: update bot name format to include [bot] suffix in tests and docs

- Update test cases to use correct bot actor names with [bot] suffix
- Update documentation example to show correct bot name format
- Align with GitHub's actual bot naming convention

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

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

* feat: normalize bot names for allowed_bots validation

- Strip [bot] suffix from both actor names and allowed bot list for comparison
- Allow both "dependabot" and "dependabot[bot]" formats in allowed_bots input
- Display normalized bot names in error messages for consistency
- Add comprehensive test coverage for both naming formats

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

---------

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

docs/usage.md

@@ -42,6 +42,8 @@ jobs:
           # Optional: grant additional permissions (requires corresponding GitHub token permissions)
           # additional_permissions: |
           #   actions: read
+          # Optional: allow bot users to trigger the action
+          # allowed_bots: "dependabot[bot],renovate[bot]"
 ```
 
 ## Inputs
@@ -76,6 +78,7 @@ jobs:
 | `additional_permissions`       | Additional permissions to enable. Currently supports 'actions: read' for viewing workflow results                                     | No       | ""        |
 | `experimental_allowed_domains` | Restrict network access to these domains only (newline-separated).                                                                    | No       | ""        |
 | `use_commit_signing`           | Enable commit signing using GitHub's commit signature verification. When false, Claude uses standard git commands                     | No       | `false`   |
+| `allowed_bots`                 | Comma-separated list of allowed bot usernames, or '\*' to allow all bots. Empty string (default) allows no bots                       | No       | ""        |
 
 \*Required when using direct Anthropic API (default and when not using Bedrock or Vertex)