feat(manifest): trusted agent forge identity and guidance

Implements PRD prd-new-trusted-agent-forge-identity. Moves author identity
and named forge configurations onto the trusted, host-only agent definition,
and lets a bottle repository optionally associate a git-gate repo with one of
the agent's forge aliases.

- Agent-owned identity: new `author` (name/email) and `forge-accounts`
  (alias -> canonical Gitea /api/v1 origin + host `token_secret` ref) on the
  agent manifest. `author` populates the bottle's git user.name/user.email.
- Remove `git-gate.user` from both agents and bottles; fail with a migration
  pointer to `author`. `git-gate` is no longer accepted on an agent.
- Bottle git-gate repos gain optional `forge: <alias>`, resolved against the
  selected agent's forge-accounts at composition (fail-closed on unknown).
- Fail-closed Gitea API URL validation (https, no userinfo/query/fragment,
  /api/v1 base, host lowercased, trailing slash normalized, host dedup).
- Proxy-held credential: synthesize one inspected, token-authenticated egress
  route per referenced forge alias, scoped to the origin + API prefix. The
  token is resolved from the host env at launch into the egress proxy only —
  never the bottle env, prompt, gitconfig, or workspace.
- Generated, non-secret forge workflow guidance appended to the agent prompt
  for associated repos (API base, branch-backed PR flow, AGit-ref prohibition,
  mutation verification); omitted when no repo declares a forge.
- Agents become home-only: cwd `.bot-bottle/agents` no longer contributes,
  overrides, or is selectable; warned-and-ignored like cwd bottles.
- Docs: README examples, PRD 0011 supersession note, manifest schema docstring.
- Tests: new test_forge_identity suite; legacy git-gate.user/cwd tests updated
  to the agent-owned identity model.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/unit/test_docker_provision_git_user.py

@@ -9,6 +9,7 @@ from __future__ import annotations
 
 import tempfile
 import unittest
+from dataclasses import replace
 from pathlib import Path
 from unittest.mock import MagicMock
 
@@ -21,7 +22,7 @@ from bot_bottle.backend import Bottle, BottleSpec, ExecResult
 from bot_bottle.backend.docker.bottle_plan import DockerBottlePlan
 from bot_bottle.egress import EgressPlan
 from bot_bottle.git_gate import GitGatePlan
-from bot_bottle.manifest import ManifestIndex
+from bot_bottle.manifest import ManifestGitUser, ManifestIndex
 
 
 class _Provider(AgentProvider):
@@ -50,15 +51,39 @@ def _plan(*, git_user: dict | None = None,  # type: ignore
           user_cwd: str = "/tmp/x",
           stage_dir: Path | None = None) -> DockerBottlePlan:
     bottle_json: dict = {}  # type: ignore
-    if git_user is not None:
-        bottle_json["git-gate"] = {"user": git_user}
     if git_repos is not None:
         bottle_json.setdefault("git-gate", {})["repos"] = git_repos
+    # Identity now lives on the agent's `author` block; at composition it
+    # populates manifest.bottle.git_user, which provision_git reads
+    # (production unchanged). When the caller passes a full name+email we
+    # route it through `author`; the name-only / email-only cases (which
+    # exercise provision_git emitting a single `git config` line) can't be
+    # expressed via `author` (both fields required), so we inject the
+    # partial ManifestGitUser onto the composed bottle directly.
+    agent_json: dict = {"skills": [], "prompt": "", "bottle": "dev"}  # type: ignore
+    full_author = (
+        git_user
+        if git_user and git_user.get("name") and git_user.get("email")
+        else None
+    )
+    if full_author is not None:
+        agent_json["author"] = full_author
     index = ManifestIndex.from_json_obj({
         "bottles": {"dev": bottle_json},
-        "agents": {"demo": {"skills": [], "prompt": "", "bottle": "dev"}},
+        "agents": {"demo": agent_json},
     })
     manifest = index.load_for_agent("demo")
+    if git_user is not None and full_author is None:
+        manifest = replace(
+            manifest,
+            bottle=replace(
+                manifest.bottle,
+                git_user=ManifestGitUser(
+                    name=git_user.get("name", ""),
+                    email=git_user.get("email", ""),
+                ),
+            ),
+        )
     spec = BottleSpec(
         manifest=index, agent_name="demo",
         copy_cwd=copy_cwd, user_cwd=user_cwd,