chore: remove dev artifacts from installer scan surface (#465)

* chore: remove dev artifacts from installer scan surface

Hermes (and other harnesses that clone raw GitHub instead of honoring
.clawhubignore) scan files that never reach an installed skill, producing
a wall of false-positive security findings. Remove the stale SKILL-original.md
backup, internal docs/plans and docs/test-results, and release-notes.md so
the scanned tree matches what actually ships.

These were already excluded from the ClawHub bundle via .clawhubignore and
from git archives via .gitattributes export-ignore. No runtime files change.

Refs #464

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* docs: drop dangling SKILL-original.md reference in AGENTS.md

Greptile-flagged: the deletion left a 'kept for reference only' pointer to
the removed file. Refs #465

---------

Co-authored-by: Matt Van Horn <455140+mvanhorn@users.noreply.github.com>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

AGENTS.md

@@ -3,14 +3,14 @@
 Agent Skills package for researching any topic across Reddit, X, YouTube, and web. Installable across Claude Code (most common host), Codex, Cursor, GitHub Copilot, Gemini CLI, and 50+ other [Agent Skills](https://agentskills.io) hosts. Python scripts with multi-source search aggregation.
 
 ## Structure
-- `skills/last30days/SKILL.md` — canonical skill definition / runtime spec the model reads when the slash command fires (`SKILL-original.md` at repo root is the historical v1 spec, kept for reference only)
+- `skills/last30days/SKILL.md` — canonical skill definition / runtime spec the model reads when the slash command fires
 - `skills/last30days/scripts/last30days.py` — main research engine
 - `skills/last30days/scripts/lib/` — search, enrichment, rendering modules
 - `skills/last30days/scripts/lib/vendor/bird-search/` — vendored X search client
 - `docs/solutions/` — documented solutions to past problems (bugs, best practices, workflow patterns), organized by category with YAML frontmatter (`module`, `tags`, `problem_type`)
 - `CONCEPTS.md` — shared domain vocabulary (Skill, Engine, Harness, Beta channel) — relevant when orienting to the codebase or discussing project terminology
 - `CONFIGURATION.md` — user-facing knobs (env vars, flags, per-host install patterns); keep in sync per the rules below
-- `CHANGELOG.md` / `release-notes.md` — release history and human-readable notes (CHANGELOG = structured, release-notes = launch copy)
+- `CHANGELOG.md` — structured release history (launch copy lives in GitHub Releases)
 - `HERMES_SETUP.md` — install instructions for the Hermes harness specifically
 
 ## Orientation