Fix perPage parameter name in actions_list schema

[karpovantonme]

Summary

actions_list declares per_page in its input schema, but the handler reads pagination through OptionalPaginationParams, which looks for perPage. Whatever the client sends is dropped and perPage always falls back to the default 30.

Why

page in the same schema matches and works, so it is just the one name. Every other tool using OptionalPaginationParams gets its schema from WithPagination, which spells it perPage; actions_list is the only place where the pagination properties are written out by hand. projects.go declares per_page too, but reads it back under the same name, so I left that one alone.

Built both binaries and called the tool over stdio against this repo:

before, client sends per_page=1  -> 30 runs   (dropped)
before, client sends perPage=1   ->  1 run    (control: the code works, the name is wrong)
after,  client sends perPage=1   ->  1 run

What changed

• pkg/github/actions.go: per_page -> perPage in the actions_list schema
• __toolsnaps__/actions_list.snap regenerated with UPDATE_TOOLSNAPS=true
• README regenerated with script/generate-docs

MCP impact

• Tool schema or behavior changed

One property is renamed. Clients that were sending per_page were already being ignored, so nothing that worked before stops working.

Prompts tested (tool changes only)

"List the most recent workflow run in github/github-mcp-server" -- with a page size, this is the case that was silently returning 30 items.

Security / limits

• No security or limits impact

Tool renaming

• I am not renaming tools as part of this PR

Lint & tests

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

Docs

• Updated (README / docs / examples)