chore: remove redundant inline comments across all crates

[tlongwell-block]

Summary

Remove ~120 inline comments that restate what self-evident code already says, without explaining why. Zero code or functionality changes — only comment lines deleted.

34 files changed across 12 crates · 164 lines removed

What was removed

Comments that narrate the next line of code:

// Create the collection.          ← before create_collection()
// Parse optional type filter.     ← before a match on query params
// Clean up.                       ← before a delete call
// 1. Evaluate condition.          ← numbered step labels
// Send the request.               ← test narration
// Fetch the feed.                 ← before client.get(&feed_url)

What was kept

• All /// and //! doc comments — untouched
• Section separators (// ── Helpers ───────)
• WHY explanations (SSRF rationale, backoff reset logic, race condition notes, TOCTOU warnings)
• Safety & security notes (⚠️ SECURITY: Do NOT log auth_token)
• Non-obvious behavior (JSON_CONTAINS semantics, NIP protocol references, type cast explanations)
• TODO / FIXME / HACK / NOTE markers
• Test scenario descriptions that add real clarity

Verification

• cargo check ✅
• Diff is comment-only — the only two non-pure-comment-line changes are trailing inline comments removed from the end of existing code lines (the code on those lines is identical before and after)

Breakdown by crate

Crate	Files	Comments Removed
sprout-test-client	4	~27
sprout-relay	13	~25
sprout-workflow	3	24
sprout-db	4	~19
sprout-huddle	2	8
sprout-mcp	2	5
sprout-core	1	4
sprout-auth	2	3
sprout-search	1	3
sprout-proxy	1	2
sprout-audit	1	1
sprout-pubsub	0	0 (already clean)