docs(agents): correct install-propagation claim and fill in build/test gaps

AGENTS.md said "edits in the working tree propagate live to every harness"
after `npx skills add . -g -y`, but the install actually drops a real
(frozen-at-install-time) copy at ~/.agents/skills/<name>/ and per-host
symlinks point at *that copy*, not at the working tree. Clarify the
mechanism and offer two ways forward: re-run `npx skills add` to sync,
or replace the install copy with a working-tree symlink for live-edit.

Also fill in two gaps a fresh agent hits on entry:
- `uv run pytest` commands for the ~89-file test suite (no test runner
  was documented before)
- Python 3.12+ / `uv` / `.venv/` convention
- Brief doc map: CONFIGURATION.md, SKILL.md vs SKILL-original.md,
  CHANGELOG.md / release-notes.md, HERMES_SETUP.md

AGENTS.md

@@ -9,6 +9,10 @@ Agent Skills package for researching any topic across Reddit, X, YouTube, and we
 - `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
+- `SKILL.md` (under `skills/last30days/`) — canonical 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
+- `CHANGELOG.md` / `release-notes.md` — release history and human-readable notes (CHANGELOG = structured, release-notes = launch copy)
+- `HERMES_SETUP.md` — install instructions for the Hermes harness specifically
 
 ## Orientation
 - This is an Agent Skills package, not a CLI tool. The product is the slash-command-invoked skill (`/last30days <topic>` in most harnesses); `scripts/last30days.py` is implementation. Claude Code is the most common host but not the only one — features must work across every harness the skill installs into.
@@ -22,9 +26,18 @@ Agent Skills package for researching any topic across Reddit, X, YouTube, and we
 python3 skills/last30days/scripts/last30days.py "test query" --emit=compact
 npx skills add . -g -y   # one-time: symlink this repo into every detected harness's skill dir
 
+# Tests (pytest, ~89 files under tests/, configured in pyproject.toml)
+uv run pytest                              # full suite
+uv run pytest tests/test_dedupe_v3.py      # single file
+uv run pytest tests/test_dedupe_v3.py -k some_case   # single case
+uv run pytest --cov                        # with coverage (skips lib/vendor/)
+```
+
+Python 3.12+ required. Use `uv` for the env; the venv lives at `.venv/`.
+
 ## Rules
 - `lib/__init__.py` must be bare package marker (comment only, NO eager imports)
-- One-time setup: `npx skills add . -g -y` creates symlinks from each detected harness's skill dir to this repo. Edits in the working tree propagate live to every harness — no re-deploy step needed.
+- One-time setup: `npx skills add . -g -y` copies the skill into `~/.agents/skills/<name>/` (real directory) and, for harnesses that support symlinked skill dirs, drops a per-host symlink pointing at that copy. **Working-tree edits do NOT propagate automatically** — the `~/.agents/skills/<name>/` copy is frozen at install time. To sync after edits, re-run `npx skills add . -g -y`. For live-edit on a dev machine, replace the install copy with a symlink to the working tree: `ln -sfn "$PWD/skills/last30days" ~/.agents/skills/last30days` (run from the repo root).
 - Git remote: origin = public (`mvanhorn/last30days-skill`)
 
 ## Security hygiene