宜博 / lemongraph

New target projects never got .claude/agents/*.md deployed, so their first
Planner call always failed immediately (claude --agent planner finds nothing
in cwd) -- self-target usage never noticed since those files are already
committed as part of this repo. create_project() now deploys and commits
them alongside the existing .graphlemon/ init commit.

Also: unroutable execution failures were recorded as a bare
blocked_reason='execution_error' with no way to see what actually broke.
scheduler._block_task()/task_execution._mark_blocked() now persist the real
exception message into execution_event.payload (blocked_reason itself is
unchanged -- budget_guardrail matches its exact value elsewhere).

Found via a real console Start-button failure on a freshly created project;
see docs/implementation-gap-analysis.md for the full writeup.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Implements c_project_create (03-C §3.0) as a plain function for U-007 to
wire up later: idempotent by target_folder_path, creates .graphlemon/ +
one init commit in an existing git repo, PATH_NOT_FOUND/PATH_NOT_WRITABLE/
GIT_INIT_DECLINED per contract, never silently `git init`s (02-V §2.1).

Also corrects a real SDD-vs-plan conflict found while scoping this Unit:
development-plan.md's U-002 line cited architecture doc §7.3's directory
tree (.claude/agents/, skills/, top-level runs/) as what to create inside
a target project. But §13.1 (a later, confirmed decision) states those are
graphlemon's own platform-repo assets (U-003 scope), and 01-M's own
graphlemon_subdir_initialized field already points at §13.2, whose target-
project tree is only .git/ + .graphlemon/ + the target's pre-existing
src/. §7.3 predates the "target project is an independent code space"
pivot and was superseded by it. Corrected development-plan.md,
unit_matrix.json, CLAUDE.md, and 05-实施约束与依赖.md accordingly (user
confirmed, 2026-07-31).

23 stdlib unittest cases (src/test_schema.py + new src/test_project_scaffold.py),
all passing.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>