feat: add agentcore browser tool

[craigh33]

Summary

Adds tools/agentcorebrowser, a constrained ADK tool for Amazon Bedrock AgentCore Browser. It supports session start/status/stop plus CDP-backed navigate, extract_text, and screenshot actions with host policy checks and artifact-backed screenshots.

Also adds a runnable examples/bedrock-agentcore-browser, package docs, tests, and moves the Nova Web Grounding note from the root README into tools/novagrounding/README.md.

Type of change

• Bug fix (non-breaking change that fixes an issue)
• New feature / enhancement (non-breaking change that adds behavior)
• Breaking change (fix or feature that could break existing callers)
• Documentation only
• Build / CI / tooling
• Refactor / test / chore (no user-visible behavior change)

Testing

• make test
• make lint (or equivalent local golangci-lint)
• Example Created/Updated: added examples/bedrock-agentcore-browser

Additional verification: make build; commit hooks passed.

Checklist

• I ran pre-commit run --all-files (or equivalent local hooks).
• My change follows existing patterns in this repository (naming, layout, error handling).
• I updated docs when behavior, setup, or public API surface changed (if applicable).
• I considered backwards compatibility for library consumers (if applicable).

Related issues

Fixes #98

[Copilot]

Pull request overview

Adds a new ADK tool package (tools/agentcorebrowser) that exposes a constrained subset of Amazon Bedrock AgentCore Browser capabilities (session lifecycle + CDP-backed navigate/text extraction/screenshot), along with tests, docs, and a runnable example. Also moves the Nova Web Grounding documentation out of the root README into tools/novagrounding/README.md.

Changes:

• Introduce agentcore_browser tool with session start/status/stop and constrained CDP actions (navigate, extract_text, screenshot) plus host policy checks and artifact-backed screenshots.
• Add unit tests and a runnable example CLI under examples/bedrock-agentcore-browser.
• Update docs: new tool README, new Nova grounding README, and root README example list adjustments.

Reviewed changes

Copilot reviewed 9 out of 10 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
tools/agentcorebrowser/tool.go	Implements the AgentCore Browser ADK tool, including CDP connection logic and host policy checks.
tools/agentcorebrowser/tool_test.go	Adds unit tests for config validation, host policy, CDP actions, and artifact saving.
tools/agentcorebrowser/README.md	Documents tool usage, behavior, and required IAM permissions.
examples/bedrock-agentcore-browser/main.go	Runnable example wiring the tool into an ADK agent/runner.
examples/bedrock-agentcore-browser/README.md	Example setup and IAM documentation.
examples/bedrock-agentcore-browser/Makefile	Adds a simple make run wrapper for the example.
tools/novagrounding/README.md	Adds Nova grounding docs previously in the root README.
README.md	Adds the AgentCore Browser example to the list and removes the embedded Nova grounding section.
go.mod	Adds bedrockagentcore and makes gorilla/websocket a direct dependency.
go.sum	Records new module checksums for the added dependencies.

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Copilot reviewed 9 out of 10 changed files in this pull request and generated 2 comments.

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Pull request overview

Copilot reviewed 13 out of 15 changed files in this pull request and generated no new comments.