refactor: prefix all manifest data classes with Manifest

Avoids name collisions with same-named runtime/plugin classes
(e.g. manifest AgentProvider vs plugin AgentProvider ABC,
manifest EgressRoute vs runtime EgressRoute). Renamed:

  AgentProvider        → ManifestAgentProvider   (manifest_agent.py)
  Agent                → ManifestAgent            (manifest_agent.py)
  EgressRoute          → ManifestEgressRoute      (manifest_egress.py)
  PathMatch            → ManifestPathMatch        (manifest_egress.py)
  HeaderMatch          → ManifestHeaderMatch      (manifest_egress.py)
  MatchEntry           → ManifestMatchEntry       (manifest_egress.py)
  EgressConfig         → ManifestEgressConfig     (manifest_egress.py)
  Bottle               → ManifestBottle           (manifest.py)
  ProvisionedKeyConfig → ManifestProvisionedKeyConfig (manifest_git.py)
  GitEntry             → ManifestGitEntry         (manifest_git.py)
  GitUser              → ManifestGitUser          (manifest_git.py)

bot_bottle/backend/__init__.py

@@ -43,7 +43,7 @@ from ..agent_provider import AgentProvisionPlan, get_provider
 from ..egress import EgressPlan
 from ..git_gate import GitGatePlan
 from ..log import die, info
-from ..manifest import GitEntry, Manifest
+from ..manifest import ManifestGitEntry, Manifest
 from ..supervise import SupervisePlan
 from ..util import expand_tilde
 from ..workspace import WorkspacePlan
@@ -297,7 +297,7 @@ class BottleBackend(ABC, Generic[PlanT, CleanupT]):
                     f"Create it under ~/.claude/skills/, then re-run."
                 )
 
-    def _validate_git_entries(self, entries: Sequence[GitEntry]) -> None:
+    def _validate_git_entries(self, entries: Sequence[ManifestGitEntry]) -> None:
         """Each entry's IdentityFile must exist on the host (after
         expanding leading ~) — the git-gate copies it in at start time
         to authenticate the upstream push (PRD 0008). Shape is already