fold project.yaml into pubspec.yaml

pubspec.yaml is now the single source of truth for version and
project metadata. Makefile reads version from pubspec.yaml. All
references to project.yaml across CLAUDE.md, CHANGELOG.md,
decisions, and skills updated.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

decisions/architecture.md

@@ -108,7 +108,7 @@ Core, rendering, IPC, kernel, panel manager.
 - **Date:** 2026-04-20 (was ADR 0006)
 - **Decision:** The CLI is organised into **subsystems**. Each subsystem owns a noun, a set of verbs, and a set of events. The set is closed at any point in time (documented); growth is additive (new verbs, new events — never renaming existing ones without a version bump). Initial subsystems (by tier): `pane`, `tab`, `open`, `editor`, `panel`, `tree`, `git`, `pql`, `canvas`, `graph`, `theme`, `settings`, `project`. Two umbrella entry points sit outside any subsystem: `clide tail --events [--filter <subsystem>[:<id>]]` and `clide status`. Command shape: `clide <subsystem> <verb> [<positional>...] [--flag ...] [-- argv...]`. Exit codes parity with pql (`0/1/2/3/4` + `64-78` sysexits reserved); diagnostic JSON on **stderr** on non-zero exit; stdout stays machine-parseable on success. Events are JSON objects, one per line, with `v`, `ts`, `type` (`<subsystem>.<verb_past|noun_changed>`), `subsystem`, `id`, and `payload`; binary payloads base64. Every state-changing command emits at least one event; read-only commands emit nothing. Replay buffer per subsystem (default depth 16) so late subscribers still see recent effects. Parity rule: every UI affordance has a matching CLI verb (or a follow-up task naming the verb); every CLI verb surfaces in the UI (or documents why it's Claude-only).
 - **Context:** [D-001](#d-001-cli-first-not-mcp) established that Claude drives clide via a Bash CLI. That decided the *channel* — it did not define the *surface*. CLAUDE.md stated the rule colloquially ("every CLI subcommand has a UI affordance … if you add one side without the other, the feature is incomplete"); this record restates it as an implementable contract that satisfies user/Claude parity, daemon-as-authoritative-state, and pql-style ergonomics at once.
-- **Rationale:** Surface is enumerable — adding a subsystem means adding a row and specifying verbs + events. Wire schema is versioned (`v: 1` starting point; compatibility breaks bump the major and land alongside a `project.yaml` `schema_version:` bump — see [Q-005](questions-architecture.md#q-005-ipc-wire-format-stability)). Events are the only UI→app state channel; the Flutter app does not poll. Extensions inherit this — a Dart extension publishes a subsystem; the same registration pipeline exposes it to Claude via the CLI.
+- **Rationale:** Surface is enumerable — adding a subsystem means adding a row and specifying verbs + events. Wire schema is versioned (`v: 1` starting point; compatibility breaks bump the major and land alongside a `pubspec.yaml` `schema_version:` bump — see [Q-005](questions-architecture.md#q-005-ipc-wire-format-stability)). Events are the only UI→app state channel; the Flutter app does not poll. Extensions inherit this — a Dart extension publishes a subsystem; the same registration pipeline exposes it to Claude via the CLI.
 - **Cost:** Replay-buffer memory per subsystem (cheap — most emit seldom). Back-pressure on firehose streams ([Q-002](questions-architecture.md#q-002-back-pressure-on-event-streams)), authorisation granularity ([Q-001](questions-architecture.md#q-001-authorisation-granularity)), and event persistence ([Q-003](questions-architecture.md#q-003-event-persistence-audit-undo)) are all deferred until Tier 1 is in real use.
 - **Raised by:** 2026-04-20 planning.