Clarify or align Reddit comments fetch limit vs MAX_COMMENTS

[gdiab]

Context

Claude re-review on PR #8 noted a readability/intent mismatch in the Reddit adapter constants.

Reference: #8 (comment)

Problem

src/adapters/reddit-adapter.ts requests comments with limit=8, but later caps collected comments at MAX_COMMENTS = 5.

This may be intentional (buffering for filtered/deleted entries), but the intent is not documented and can look inconsistent to future maintainers.

Proposed change

Pick one of these approaches:

• Document intent with a brief code comment near the fetch URL/constant.
• Or align values if extra buffering is not needed.

Acceptance criteria

• The mismatch is either documented or eliminated.
• Behavior remains unchanged unless we intentionally decide to alter collection limits.
• Tests continue to pass.

Priority

Minor / non-blocking follow-up from PR #8.