[Sync] adopt unified stow layout from the private repo

Mirrors the private dots tree at 900bdda: one shared base plus per-host
overlays, replacing the old flat .config/ layout (last synced 2026-06-28).

- packages: common/ gui/ wm/ lw/ fl/ + install.sh and bin/ tooling (dotsync,
  reconcile-hyde.sh)
- new README (layout, deploy order, HyDE dependency), plus ToDo.md and
  HYDE-UPDATE.md
- current HyDE waybar rig (layouts/, cava), pi agent extensions, claude/
  config, tmux, presenterm, aichat roles
- drops stale duplicates and generated cruft that should never have been
  tracked: the second top-level .pi/ copy, btop.log, zellij config.kdl.bak,
  fish_variables, nvim codecompanion.lua
- .pi/agent/auth.json is gitignored now; auth.json.example ships instead
- fl/ and wm/ hypr themes/ stay untracked (HyDE-generated per machine, per
  the root .gitignore)

common/.config/claude/skills/pr-description/SKILL.md

@@ -0,0 +1,36 @@
+---
+description: Draft a ready-to-paste PR description by filling this repo's GitHub PR template from the branch diff and commits, then copy it to the clipboard. Use after finishing a feature.
+argument-hint: [base-branch]
+disable-model-invocation: true
+allowed-tools: Bash(git diff:*), Bash(git log:*), Bash(git merge-base:*), Bash(git symbolic-ref:*), Bash(git rev-parse:*), Bash(git show-ref:*), Bash(ls:*), Bash(cat:*), Bash(wl-copy:*), Bash(mktemp:*), Bash(rm:*), Read, Glob
+---
+
+# Draft this branch's PR description
+
+This repo's PR template (first match), plus the branch's changes:
+
+!`for f in .github/pull_request_template.md .github/PULL_REQUEST_TEMPLATE.md docs/pull_request_template.md docs/PULL_REQUEST_TEMPLATE.md PULL_REQUEST_TEMPLATE.md pull_request_template.md; do if [ -f "$f" ]; then echo "=== PR template: $f ==="; cat "$f"; found=1; break; fi; done; if [ -z "$found" ]; then if [ -d .github/PULL_REQUEST_TEMPLATE ]; then echo "=== template dir .github/PULL_REQUEST_TEMPLATE/ (pick one) ==="; ls .github/PULL_REQUEST_TEMPLATE/; else echo "(no PR template found — use the fallback structure)"; fi; fi`
+
+!`b=$(git symbolic-ref --short -q refs/remotes/origin/HEAD 2>/dev/null | sed 's@^origin/@@'); [ -z "$b" ] && { git show-ref -q --verify refs/heads/main && b=main || b=master; }; m=$(git merge-base "$b" HEAD 2>/dev/null); echo "Branch: $(git rev-parse --abbrev-ref HEAD 2>/dev/null)  Base: $b  Range: ${m:-?}..HEAD"; echo; echo "Commits:"; git --no-pager log --oneline "${m}..HEAD" 2>/dev/null; echo; echo "Files changed:"; git --no-pager diff --stat "${m}...HEAD" 2>/dev/null`
+
+## What to do
+
+1. **Resolve the base branch** (use the invocation argument if given — **$ARGUMENTS** — else the
+   detected base) and read the full diff + commit messages for `merge-base..HEAD`.
+2. **Fill the PR template shown above** from the *actual* changes:
+   - Write the Summary / motivation and any "Implementation Notes" from the diff and commits.
+   - Fill the **Type of Change** field or boxes with the kinds that genuinely match (feature /
+     fix / refactor / perf / tests / docs / chore).
+   - Tick `Self-reviewed` and `LLM-assisted` if those boxes exist.
+   - **Leave verification boxes unchecked** — e.g. "tests passed", "`validate:full` passes",
+     "pre-commit hooks passed". I confirm those myself; never tick them for me.
+   - Fill **Related Issues** from issue numbers in the branch name or commit trailers; delete any
+     placeholder lines you can't fill (never leave a dangling `Closes #`), and drop the whole
+     section if there are no issues to reference.
+   - If a multi-template dir was listed (no single file), pick the most fitting one and say which.
+   - **If no template exists**, use this fallback: `## Summary` / `## Changes` / `## Testing` /
+     `## Notes`.
+3. **Output** the filled description as a single fenced ```markdown code block, copy-paste ready.
+4. **Copy it to the clipboard**: write the same markdown to a temp file (`mktemp`) and run
+   `wl-copy < "$tmpfile"`, then remove the temp file. Tell me it's on the clipboard.
+5. **Do not** create, push, or edit the PR (`gh pr ...`) — I add the text to the PR myself.