Trim comments across Rust and webapp source to direct one-liners (ticket 030)

Pass over src/*.rs, webapp/src/**, and the in-app "?" docs prose:
condensed multi-paragraph doc comments to single lines that state the
non-obvious why, deleted comments that only restated adjacent code, and
tightened the Docs.tsx help-panel wording. No logic, structure, or code
formatting changed — verified via cargo test (143 passed) and
tsc -b && vite build.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XFUNZwCvz3kcod3352ZR2o

tickets/030-comment-cleanup.md

@@ -1,35 +0,0 @@
-# 030 — Cut comments down to clear, direct one-liners
-
-## Summary
-
-Pass over the Rust codebase, the webapp source, and the webapp's in-app docs,
-trimming every comment/doc-comment to a single clear, direct line where one is
-needed at all, and removing it outright where it isn't.
-
-## Scope
-
-- `src/*.rs`: many modules currently carry multi-paragraph `///`/`//!` blocks
-  (e.g. `src/settings.rs`'s module doc and per-method docs). Keep only what
-  explains a non-obvious *why* (a constraint, an invariant, a workaround);
-  drop restatements of what the code already says via naming.
-- `webapp/src/**`: same treatment for inline comments and any JSDoc-style
-  blocks.
-- The webapp's in-app documentation content (surfaced via the "?" help icons
-  from [021](021-docs-contextual-help.md)) — reduce prose there the same way:
-  clear and direct, not verbose.
-- This is a mechanical cleanup pass, not a refactor — don't change behavior or
-  restructure code while doing it; keep it reviewable as a comments-only diff
-  where possible.
-
-## Acceptance criteria
-
-- No multi-line comment blocks remain outside of license/generated headers
-  (if any).
-- Every remaining comment states a non-obvious reason, not a restatement of
-  the adjacent code.
-- `cargo test` and the webapp build/tests still pass (confirms nothing beyond
-  comments changed).
-
-## Depends on
-
-None.