Add ce_sessions schema (onSchemaInit), CeSessionStore (via
ctx.taskStore.getDatabase()), and CeOrchestrator driving a stage's skill on the
U4 interactive seam: streams thinking/text, persists questions as
awaiting_input, writes the stage artifact on complete, and auto-saves +
emits an observable event on interrupt/error (never silent loss). Lifecycle:
launching/active/awaiting_input/completed/error/interrupted with resume and an
interval-relative staleness rubric. Start/answer/resume/get-state routes.
Streaming transport is client polling of the get-session-state route for v1:
plugin routes have no native SSE and the loader emitEvent is a logging stub, so
true server push needs a host publish-to-/api/events seam (tracked follow-up).
Skill discovery is cwd+prompt-based; forwarding install paths through the seam
is a tracked follow-up.
Bundle pinned copies of 7 CE pipeline-stage skills (strategy, ideate,
brainstorm, plan, work, code-review, compound) under src/skills/ and declare
them via PluginSkillContribution. Empirical finding: the skills contribution
alone does not make a SKILL.md resolvable in a session -- the engine ingests it
as a name only. So onLoad runs an idempotent, isolation-guarded physical install
into a plugin-local .fusion-ce-skills/ dir (never a global ~/.claude/skills),
which the engine skill-resolver can then discover. Proven against the real
loadSkills + resolveSessionSkills pipeline.
