feat(skills): reddit-reading and rss-feeds bundled skills, multi-platform sweep guidance

Two zero-install research skills plus routing guidance, ported as ideas
(not code) from the Agent Reach skill's per-platform backend routing.

reddit-reading (skills/social-media): subreddit listings, site/subreddit
search, threads with comments, user pages. Live-verified from a datacentre
IP: www .json, api.reddit.com, old.reddit, r.jina.ai and the browser tool
all return 403 / an empty shell / a humanity check; the Atom .rss endpoints
are the only anonymous path and are throttled to ~1 request/min/IP. The
script waits out the x-ratelimit-reset window once and retries, and
switches to the OAuth API (scores, nested comments, ~100 req/min) when
REDDIT_CLIENT_ID/SECRET are present. `doctor` reports the active backend.

rss-feeds (skills/research): RSS 2.0 / RSS 1.0 / Atom / JSON Feed parsing
with UTC-normalised dates, --since/--limit, and feed discovery behind a
page URL (<link rel=alternate>, then well-known paths). Stdlib only; the
optional blogwatcher skill remains the stateful many-feed reader and now
points at this one for one-off reads.

grounded-citations gains a "Multi-Platform Sweeps" section routing
"what are people saying about X" tasks across web, Reddit, feeds, video,
code and X with per-platform attribution and coverage-gap reporting;
competitor-news-monitor references the new sources.

Tests: two invariant tests per skill (format normalisation + discovery;
anonymous 429 handling + OAuth routing/flattening), no network. The
reddit test caught a real bug: the feed footer's "/u/author" leaked into
post bodies.

optional-skills/research/blogwatcher/SKILL.md

@@ -24,6 +24,7 @@ Track blog and RSS/Atom feed updates with the `blogwatcher-cli` tool. Supports a
 - **Recurring watch — use the cronjob tool's `monitor` field, not a bare schedule.** `monitor` runs a script each tick and only wakes the agent when output changes: set it to a script that runs `blogwatcher-cli scan >/dev/null 2>&1 && blogwatcher-cli articles` (deterministic output; new articles = changed output = agent wakes with the diff injected). Unchanged ticks cost zero LLM calls. Set `deliver` to route digests to a chat/channel; add `continuity: true` so consecutive digests can dedupe.
 - **Reading an article the user asks about**: `web_extract([url])` on the article URL from `blogwatcher-cli articles` — do not re-scrape by hand.
 - **One-off "watch this page for changes" without feed semantics**: skip this skill; the cronjob tool's `monitor` field accepts an http(s) URL directly.
+- **One-off read of a feed or a site's latest posts, nothing to install**: the bundled `rss-feeds` skill (`scripts/feed.py read URL`); blogwatcher earns its install when you track many feeds with read/unread state.
 - **Company/competitor tracking with analysis and citations**: prefer the `competitor-news-monitor` skill; blogwatcher is the lighter raw-feed layer it can sit on.
 
 ## Installation