Prevent inputs param from being stripped from actions_run_trigger tool schema

[kerobbi]

Summary

Adds a properties field to the inputs param schema in actions_run_trigger so it is not dropped from the tool schema due to OAI strict mode schema requirements. Also replaces a silent type assertion with OptionalParam for proper error handling on malformed inputs.

Why

Fixes #1877

The inputs parameter was defined as type: "object" with no properties field, and OAI strict mode requires object types to include a properties field. Without it, the parameter is not visible to GPT models.

What changed

• Added Properties: map[string]*jsonschema.Schema{} to the inputs param schema
• Replaced manual type assertion for inputs with OptionalParam[map[string]any], which returns an error on type mismatch instead of silently dropping the value

MCP impact

• No tool or API changes
• Tool schema or behavior changed - inputs param now serialises with an empty properties field
• New tool added

Prompts tested (tool changes only)

• "Run the X workflow in OWNER/REPO on Y branch with these inputs: FIELD1=value1, ..."
• "Trigger the X workflow in OWNER/REPO, ref: Y. Pass these workflow inputs: FIELD1=value1, ..."

All testing was done against a mock workflow with optional params - verified across multiple models.

Security / limits

• No security or limits impact
• Auth / permissions considered
• Data exposure, filtering, or token/size limits considered

Tool renaming

• I am renaming tools as part of this PR (e.g. a part of a consolidation effort)
  • I have added the new tool aliases in deprecated_tool_aliases.go
• I am not renaming tools as part of this PR

Note: if you're renaming tools, you must add the tool aliases. For more information on how to do so, please refer to the official docs.

Lint & tests

• Linted locally with ./script/lint
• Tested locally with ./script/test

Docs

• Not needed
• Updated (README / docs / examples)

[Copilot]

Pull request overview

Fixes actions_run_trigger schema/argument handling so workflow dispatch inputs are preserved for model/tooling consumers and malformed inputs are surfaced as errors instead of being silently ignored (addresses #1877).

Changes:

• Add an explicit empty properties map to the inputs JSON schema to prevent it from being stripped during schema processing.
• Parse inputs via OptionalParam[map[string]any] to return a proper error on type mismatch.
• Update the tool schema snapshot to reflect the serialized properties: {} addition.

Show a summary per file

File	Description
pkg/github/actions.go	Ensures inputs remains in the tool schema and adds strict type-checking/error handling when inputs is provided.
pkg/github/toolsnaps/actions_run_trigger.snap	Updates the recorded schema snapshot to include inputs.properties: {}.

Copilot's findings

• Files reviewed: 2/2 changed files
• Comments generated: 1