fix: use correct octokit API for PR review comment reactions

[elithrar]

When commenting on files in a PR/lines in a PR, opencode attempts to react (with eyes) and fails with a 404, breaking the workflow. This does not occur for issue comments.

There are two different APIs for this via octokit:

1. one for issue comments - octokit.reactions.createForIssueComment
2. one for PR comments - octokit.reactions.createForPullRequestReviewComment

opencode did not distinguish between the two - in packages/opencode/src/cli/cmd/github.ts the addReaction() function only worked for issues. I noticed this in my own GH reaction handling and had to make a similar fix.

This PR fixes this by passing a commentType parameter to addReaction() and removeReaction() functions and then using that to switch on the right octokit methods.

(It appears this hasn't been a flow others have run into before? The rest of the PR comment handling looks to be there + OK)

[elithrar]

for ref:

Adding reaction...
POST /repos/elithrar/get-ratioed/issues/comments/2633462072/reactions - 404 with id 8840:A5CA:2DF98A:C80604:6944C5F7 in 130ms
118 |       request: requestOptions
119 |     });
120 |   }
Creating comment...
121 |   if (status >= 400) {
122 |     octokitResponse.data = await getResponseData(fetchResponse);
123 |     throw new RequestError(toErrorMessage(octokitResponse.data), status, {
                ^
HttpError: Not Found - https://docs.github.com/rest/reactions/reactions#create-reaction-for-an-issue-comment
   status: 404,
  request: {
  method: "POST",
  url: "https://api.github.com/repos/elithrar/get-ratioed/issues/comments/2633462072/reactions",
  headers: [Object ...],
  body: [Object ...],
  request: [Object ...],
},
 response: {
  url: "https://api.github.com/repos/elithrar/get-ratioed/issues/comments/2633462072/reactions",
  status: 404,
  headers: [Object ...],
  data: [Object ...],
},

      at fetchWrapper (../../node_modules/.bun/@octokit+request@10.0.7/node_modules/@octokit/request/dist-bundle/index.js:123:11)

Removing reaction...
GET /repos/elithrar/get-ratioed/issues/comments/2633462072/reactions?content=eyes - 404 with id 8840:A5CA:2DFD15:C8144D:6944C5F8 in 125ms
Error: Unexpected error, check log file at /home/runner/.local/share/opencode/log/2025-12-19T032644.log for more details

HttpError: Not Found - https://docs.github.com/rest/reactions/reactions#list-reactions-for-an-issue-comment
   status: 404,
  request: {
  method: "GET",
  url: "https://api.github.com/repos/elithrar/get-ratioed/issues/comments/2633462072/reactions?content=eyes",
  headers: [Object ...],
  request: [Object ...],
},
 response: {
  url: "https://api.github.com/repos/elithrar/get-ratioed/issues/comments/2633462072/reactions?content=eyes",
  status: 404,
  headers: [Object ...],
  data: [Object ...],
},

      at fetchWrapper (../../node_modules/.bun/@octokit+request@10.0.7/node_modules/@octokit/request/dist-bundle/index.js:123:15)
      at processTicksAndRejections (native:7:39)

Error: Process completed with exit code 1.