New projects from conversation (M2.5, PR B)

- propose_project(name, purpose, decisions) in a conversation goes up for
  a go-ahead (checked: a slug, not an existing project, no trailing
  question).
- On go, the provisioning checklist (D1): a repository with a README,
  protection on its default branch, the agent as a collaborator, a build
  VM, a deploy key, and the project entry as YAML with <...> to fill in.
- On "done", the agent reads its configuration again and adds the new
  project live (build_loop_agent(load=...); only additions), then checks
  what was provided (D4, verified, not assumed): permissions and
  protection as it sees them, then on a throwaway branch with an empty
  commit, a branch push must succeed and a push to the default branch and
  merging its own PR must be refused. The check's PR is closed and its
  branch deleted. Failures are said per item; nothing starts.
- Checked: the tracking issue (the distilled decisions, carrying the new
  item's ID), and the project's item, agreed and labelled `design`, whose
  first milestone is ARCHITECTURE.md and the build plan. A conversation
  waiting on provisioning doesn't close as idle.
- The walk replays exactly from its seed (item IDs too), and event IDs
  stay unique across simulated restarts, as a server's are.
- The test config holds output to 8192 tokens, under the test key's
  per-request cost cap.

Tests: new-project unit tests (checklist and its YAML parse as config, done
before the entry, what isn't set up, a checked project's record and first
PR, an existing name), protection enforced by a hook on the fake forge,
the walk proposing projects and saying done, and an e2e new project in a
repository the test operator provisions from the agent's checklist.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPQ14L3LikyefCMFBqEbKE

tests/integration/e2e_support.py

@@ -61,7 +61,7 @@ class FreshRepo:
 
 @contextlib.contextmanager
 def fresh_repo(
-    operator: GiteaClient, run: str, keys: Path, *, agent: str
+    operator: GiteaClient, run: str, keys: Path, *, agent: str, seed: bool = True
 ) -> Iterator[FreshRepo]:
     """A repository of its own for one test run, as the operator would make a
     project's (D4, D8): seeded with a small Python package, the ``agent``
@@ -88,14 +88,21 @@ def fresh_repo(
                 "content": base64.b64encode(path.read_bytes()).decode(),
             }
             for path in sorted(SEED.rglob("*"))
-            if path.is_file() and path.name != "README.md"
+            if seed and path.is_file() and path.name != "README.md"
         ]
-        operator._request(
-            "POST",
-            f"/repos/{full}/contents",
-            json={"branch": "main", "message": "Seed the test project", "files": files},
-        )
+        if files:
+            operator._request(
+                "POST",
+                f"/repos/{full}/contents",
+                json={
+                    "branch": "main",
+                    "message": "Seed the test project",
+                    "files": files,
+                },
+            )
         readme = operator._request("GET", f"/repos/{full}/contents/README.md")
+        # A new project's README says only what it is; a seeded one, the seed's.
+        text = (SEED / "README.md").read_bytes() if seed else f"# {name}\n".encode()
         operator._request(
             "PUT",
             f"/repos/{full}/contents/README.md",
@@ -103,7 +110,7 @@ def fresh_repo(
                 "branch": "main",
                 "message": "README",
                 "sha": readme["sha"],
-                "content": base64.b64encode((SEED / "README.md").read_bytes()).decode(),
+                "content": base64.b64encode(text).decode(),
             },
         )
         operator._request(