align pql client to the 1.5 exit-code contract; unvendor its skill

pql 1.5 returns exit 0 with an empty `[]` for zero matches (older pql
used exit 2), so the wrapper's "exit 2 = empty, not an error" carve-out
is obsolete — and risky, since a future exit 2 could mean a real error.
Any non-zero exit is now an error.

Also removed the repo's vendored .claude/skills/pql: it's generated by
`pql init` (which CONTRIBUTING already lists in setup, installing at user
scope), so a committed snapshot just shadows the current global skill
with stale content and drifts on every pql bump — this copy was a whole
version behind. Other vendored skills are clide-owned; pql's is pql's.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.claude/skills/pql/SKILL.md

@@ -1,193 +0,0 @@
----
-name: pql
-description: >
-  Query and plan against a markdown vault via the pql CLI. Two surfaces:
-  (1) structural queries — frontmatter, wikilinks, tags, headings, Bases,
-  DSL — use when the user asks about vault contents ("which notes…", "find
-  where…", "what tags", "who links to X", "run a Base", "query the vault");
-  (2) planning — decision records, tickets, project status — use when the
-  user asks about decisions, tickets, work items, or project planning
-  ("sync decisions", "create a ticket", "what's the plan status", "show
-  D-5", "board"). Requires `pql` on PATH. JSON on stdout; exit 2 = zero
-  matches (not an error).
----
-
-# pql — vault queries + project planning
-
-`pql` indexes a vault into SQLite and exposes structural queries plus a
-planning layer for decision records and tickets. One binary, two surfaces.
-
-## Precondition
-
-```bash
-command -v pql
-```
-
-If absent, tell the user to install from
-https://github.com/postmeridiem/pql/releases/latest. Don't install it
-yourself. Don't fall back to grep unless the user explicitly asks.
-
-## First touch: learn the vault
-
-```bash
-pql schema
-```
-
-Returns one row per frontmatter key with observed types and file counts.
-Run once per session before writing queries.
-
----
-
-## Surface 1: Vault queries
-
-### Subcommands
-
-| Command | Purpose |
-|---|---|
-| `pql files [glob]` | List indexed files; optional glob filter |
-| `pql tags [--sort count]` | Distinct tags with counts |
-| `pql backlinks <path>` | Files linking TO a path |
-| `pql outlinks <path>` | Links FROM a file |
-| `pql meta <path>` | Frontmatter + tags + outlinks + headings for one file |
-| `pql schema` | Typed frontmatter schema |
-| `pql base <name>` | Execute an Obsidian .base file |
-| `pql shell` | Interactive REPL (indexes once, then query per line) |
-| `pql query "<DSL>"` | SQL-derived DSL for complex queries |
-| `pql doctor` | Resolved vault/config/DB/index state |
-
-### DSL examples
-
-```sql
-SELECT name, fm.date WHERE fm.type = 'meeting' ORDER BY fm.date DESC LIMIT 10
-SELECT path WHERE 'project' IN tags ORDER BY path
-SELECT name, fm.prior_job WHERE fm.type = 'council-member' ORDER BY name
-```
-
-Use `--file q.pql` or `--stdin` for long queries. Don't interpolate vault
-content into the command line.
-
-### Query cookbook
-
-- **Files in folder** → `pql files 'sessions/*'`
-- **Top tags** → `pql tags --sort count --limit 20`
-- **What links to X?** → `pql backlinks members/vaasa/persona.md`
-- **Date range** → `pql query "SELECT name, fm.date WHERE fm.date BETWEEN '2024-01-01' AND '2024-12-31'"`
-- **Run a Base** → `pql base council-sessions`
-- **Inspect one file** → `pql meta members/vaasa/persona.md --pretty`
-
----
-
-## Surface 2: Planning (decisions + tickets)
-
-Planning state lives in `<vault>/.pql/pql.db` (user-authored state, not a
-cache). Decision records come from `decisions/*.md`; tickets are
-SQLite-native.
-
-### Decision subcommands
-
-| Command | Purpose |
-|---|---|
-| `pql decisions sync` | Parse decisions/*.md → upsert into pql.db |
-| `pql decisions validate` | Dry-run parse; exits non-zero on malformed records |
-| `pql decisions claim <D\|Q\|R> <domain> "title"` | Print next available ID |
-| `pql decisions list [--type X] [--domain X] [--status X]` | List decisions |
-| `pql decisions show <id> [--with-refs] [--with-tickets]` | Show with joins |
-| `pql decisions coverage` | Confirmed decisions without tickets |
-| `pql decisions refs <id>` | Cross-references involving a decision |
-
-Always `pql decisions sync` before querying if decisions/*.md may have changed.
-
-### Ticket subcommands
-
-| Command | Purpose |
-|---|---|
-| `pql ticket new <type> "title" [--decision D-NNN] [--priority P]` | Create (emits T-NNN) |
-| `pql ticket list [--status S] [--team T] [--assigned A] [--label L]` | List with filters |
-| `pql ticket show <id> [--with-context] [--with-blockers]` | Show with joins (context = ancestors + decisions + children) |
-| `pql ticket status <id[,id,...]> <new-status>` | Transition (batch via comma-separated IDs) |
-| `pql ticket assign <id> <agent>` | Set assignee |
-| `pql ticket block <id> --by <other>` | Add blocker |
-| `pql ticket unblock <id> --from <other>` | Remove blocker |
-| `pql ticket team <id> <team>` | Set team |
-| `pql ticket label <id> add\|rm <label>` | Manage labels |
-| `pql ticket board [--team T]` | Kanban board view |
-
-Ticket types: initiative, epic, story, task, bug.
-Status flow: backlog → ready → in_progress → review → done (also cancelled).
-
-### Plan subcommands
-
-| Command | Purpose |
-|---|---|
-| `pql plan status` | Dashboard: decision counts, open Qs, ticket summary, coverage gaps |
-| `pql plan export [--to FILE]` | Snapshot planning state to JSON (default: `pql-plan.json`) |
-| `pql plan import [--from FILE]` | Restore planning state from a JSON snapshot |
-
-### Versioning planning state
-
-Planning state lives in `pql.db` (gitignored). To version it in git,
-use `pql plan export` to write a committed JSON snapshot. pql does NOT
-do this automatically — the user decides when and how to trigger it:
-
-- Pre-push hook: `.githooks/pre-push` calls `pql plan export && git add pql-plan.json`
-- Sprint close: a skill or script exports + commits on milestone
-- Manual: run `pql plan export` before committing when state changed
-
-On a fresh clone, `pql plan import` restores from the snapshot.
-
-### Planning cookbook
-
-- **Sync and list confirmed** → `pql decisions sync && pql decisions list --type confirmed`
-- **Show with refs** → `pql decisions show D-5 --with-refs --pretty`
-- **Create ticket** → `pql ticket new task "implement X" --decision D-5`
-- **Batch close** → `pql ticket status T-1,T-2,T-3 done`
-- **Coverage gaps** → `pql decisions coverage`
-- **Dashboard** → `pql plan status --pretty`
-- **Snapshot for git** → `pql plan export`
-
----
-
-## Output contract (both surfaces)
-
-- **stdout:** JSON array (default); `--jsonl` for one object/line; `--pretty`; `--limit N`.
-- **stderr:** JSON diagnostics `{"level":"…","code":"pql.<phase>.<kind>","msg":"…"}`.
-- **Exit codes:**
-  - `0` — success, ≥1 result
-  - `2` — zero matches (not an error — say "no matches", not "failed")
-  - `64` — bad flag
-  - `65` — parse/compile error (pass stderr back)
-  - `66` — vault/config not found
-  - `69` — unavailable
-  - `70` — internal error
-
-## Anti-patterns
-
-- Don't pipe to `jq` for simple projections — use `--limit`, `--pretty`, `--jsonl`.
-- Don't chain `pql files` + `pql meta` — one `pql query` with WHERE.
-- Don't parse errors — pass stderr diagnostics back directly.
-- Don't forget `pql decisions sync` before querying decisions.
-- Don't try to install or upgrade pql — instruct the user if missing.
-
-## When NOT to use
-
-- **Body text search** → `grep`/`rg`.
-- **Reading file contents** → `Read` tool.
-- **Code structure** → tree-sitter / LSP.
-- **Modifying vault files** → `Write`/`Edit`. pql doesn't write to vault content.
-
-## Permissions
-
-The consuming project's `.claude/settings.json` should allow:
-
-```json
-{
-  "permissions": {
-    "allow": ["Bash(pql)", "Bash(pql *)"]
-  }
-}
-```
-
-## Updating the skill
-
-`pql skill status` reports drift. `pql skill install` writes/updates;
-`--force` overrides hand-edits. `pql doctor` also surfaces skill state.

lib/src/pql/client.dart

@@ -178,8 +178,9 @@ class PqlClient {
       );
     }
     final stderr = (r.stderr as String).trim();
-    // Exit 2 = zero matches — valid empty result, not an error.
-    if (r.exitCode != 0 && r.exitCode != 2) {
+    // pql 1.5+ returns exit 0 with an empty `[]` for zero matches, so any
+    // non-zero exit is a real error (older pql used exit 2 for empty).
+    if (r.exitCode != 0) {
       throw PqlException(
         'pql ${args.first} failed',
         exitCode: r.exitCode,