Add sssf skill, installable via the skills CLI

Port the sssf skill from ~/.agents/skills/sssf into this repo so it can be
distributed and installed with the skills CLI (skills add INDigitalStudio/skills
--skill sssf).

- Copy the skill (SKILL.md, cookbooks, references, scripts, templates, and the
  visualizer app source) into sssf/.
- Gitignore build/runtime artifacts: the visualizer's node_modules/ and dist/,
  Python bytecode, and the machine-specific repos.json.
- Make the skill location-independent: install.py now stamps the skill's real
  path into the stamped justfile's skill_dir (replacing the hardcoded
  ~/.agents/skills/sssf), so 'just obs' finds the visualizer wherever the CLI
  installed the skill.
- Update cookbooks to use <skill>/scripts/... instead of the hardcoded path,
  and document the skills CLI install command.
- Update the repo README with install instructions.

sssf/templates/justfile

@@ -0,0 +1,97 @@
+# SSSF starter recipes. Stamped by install.py, then yours to edit.
+#
+# Deliberately small. These are the handful you need on day one: run something,
+# watch it, and open the trace. Add your own as your chains grow, and see the
+# example branch for the fuller set (orchestrator agents, kill, rosters, ipi).
+
+# `.env` reaches every ADW through this, so keys work without exporting them.
+set dotenv-load
+set positional-arguments
+
+# Every recipe passes this through, so `SSSF_CONFIG=other.yaml just sdlc "..."`
+# swaps the whole roster for one run.
+config := env_var_or_default("SSSF_CONFIG", "adws/adw_sssf_config/sssf.config.yaml")
+db     := "adws/adw_data/sssf.db"
+
+# Where the sssf skill lives — the visualizer app ships with it. install.py
+# stamps the real path here at install time; edit it if you move the skill.
+skill_dir := "@SSSF_SKILL_DIR@"
+
+# list every recipe
+default:
+    @just --list
+
+# ── first run ───────────────────────────────────────────────────────────────
+
+# Proves the whole path works: config validated, session minted, agent ran,
+# envelope parsed, gates checked, trace written. Costs a few cents and changes
+# nothing in your repo, because both workflows are read-only.
+#
+# (`just --list` shows only the LAST comment line, so that one is the summary.)
+
+# start here: two cheap read-only runs, end to end
+demo:
+    @echo "1/2  adw_prompt: one agent, one prompt"
+    uv run adws/adw_prompt.py --config {{config}} --agent scout "reply with a one-line summary of this repo"
+    @echo "\n2/2  adw_scout: read-only recon"
+    uv run adws/adw_scout.py --config {{config}} "list the top-level directories in this repo and what each is for. change nothing."
+    @echo "\nboth done. now run:  just sessions    (or: just obs)"
+
+# check the roster without running anything: names, prompts, models all resolve
+validate:
+    uv run adws/adw_validate.py --config {{config}}
+
+# ── run a workflow ──────────────────────────────────────────────────────────
+# Args pass straight through: "<prompt or path/to/prompt.md>" [--adw-id X]
+
+# one agent, one prompt: just prompt "summarize this repo"
+prompt *ARGS:
+    uv run adws/adw_prompt.py --config {{config}} "$@"
+
+# read-only recon: just scout "where is auth handled"
+scout *ARGS:
+    uv run adws/adw_scout.py --config {{config}} "$@"
+
+# plan only: just plan "add a /health endpoint"
+plan *ARGS:
+    uv run adws/adw_plan.py --config {{config}} "$@"
+
+# planner, builder, commit: just plan-build "add a /health endpoint"
+plan-build *ARGS:
+    uv run adws/adw_plan_build.py --config {{config}} "$@"
+
+# plan, build, test, commit: just sdlc "add a /health endpoint"
+sdlc *ARGS:
+    uv run adws/adw_plan_build_test.py --config {{config}} "$@"
+
+# the full chain, plus review and docs: just simple-sdlc "add a /health endpoint"
+simple-sdlc *ARGS:
+    uv run adws/adw_simple_sdlc.py --config {{config}} "$@"
+
+# ── watch it ────────────────────────────────────────────────────────────────
+# Reads never block a running workflow, the db is WAL. Poll as hard as you like.
+
+# the last 10 runs
+sessions:
+    @sqlite3 {{db}} "select adw_id, status, substr(request,1,50), total_tokens, round(total_cost,4) from sessions order by started_at desc limit 10;"
+
+# phase status in sequence: just phases <adw_id>
+phases ADW_ID:
+    @sqlite3 {{db}} "select seq, name, kind, owner, status, attempt from phases where adw_id='{{ADW_ID}}' order by seq;"
+
+# the live event tail: just tail <adw_id>
+tail ADW_ID:
+    @sqlite3 {{db}} "select rowid, type, name, started_at from events where adw_id='{{ADW_ID}}' order by rowid desc limit 25;"
+
+# what a run has alive right now, with pids: just procs <adw_id>
+procs ADW_ID:
+    @sqlite3 {{db}} "select kind, name, pid, command, started_at from processes where adw_id='{{ADW_ID}}' and ended_at is null order by id;"
+
+# ── observability UI ────────────────────────────────────────────────────────
+
+# Needs bun. The db path is passed explicitly because the server runs from the
+# app dir and would otherwise look for a trace db sitting next to itself.
+
+# boot the trace UI, http://localhost:4601 (api on :4600)
+obs:
+    cd {{skill_dir}}/apps/visualizer && bun install && (SSSF_DB={{justfile_directory()}}/{{db}} bun run server/index.ts &) && bunx vite