feat(models,project_manager): add ProjectContext + 5 sub-dataclasses (Phase 2 / VC8)

Phase 2: Fix flat_config to return typed ProjectContext (FR8 / VC8)
Before: def flat_config(...) -> Metadata  (returned dict[str, Any])
After:  def flat_config(...) -> ProjectContext  (typed fat struct)
Delta:  -1 anonymous dict return type; +6 new dataclasses

Per SPEC_CORRECTION_phase_2.md, this is Option A (incremental):
- Add 6 sub-dataclasses: ProjectMeta, ProjectOutput, ProjectFiles,
  ProjectScreenshots, ProjectDiscussion, ProjectContext
- Each matches the nested dict shape of flat_config()'s actual return
- ProjectContext has dict-compat methods (__getitem__ + get) so
  consumers using .get() / [] continue to work unchanged
- ProjectContext.to_dict() returns the legacy dict shape for migration
- EMPTY_PROJECT_CONTEXT sentinel exported

File locations per spec:
- src/models.py: 6 new dataclasses + EMPTY_PROJECT_CONTEXT sentinel
- src/project_manager.py: flat_config body rewritten to construct
  ProjectContext from the proj dict (typed return type)
- tests/test_project_context_20260627.py: NEW regression-guard test file
  with 10 tests covering: imports, return type, zero defaults, full
  input, dict-compat __getitem__/get, to_dict round-trip, sentinel,
  output_dir required field, consumer patterns unchanged

Verification:
- audit_weak_types --strict: OK (96 <= 112 baseline; down from 107)
- generate_type_registry: 23 files regenerated
- 10 test_project_context_20260627 tests PASS
- All existing consumer tests pass (test_context_composition_decoupled: 2,
  test_orchestrator_pm: 3, test_orchestration_logic: 8,
  test_orchestrator_pm_history + test_context_preview_button: 7,
  test_project_manager_tracks: 4, test_track_state_persistence: 1)

VC8 (corrected) verification:
- flat_config returns ProjectContext (typed) ✓
- All 6 sub-dataclasses exist + importable ✓
- Dict-compat methods (ctx["key"], ctx.get("key")) work ✓
- output_dir REQUIRED field defaults to "" (empty, but valid) ✓
- Consumer patterns (ctx.get("output", {}).get("namespace", "project"))
  work unchanged via dict-compat ✓

Phase 2 IS COMPLETE.

src/models.py

@@ -1099,3 +1099,86 @@ def load_mcp_config(path: str) -> MCPConfiguration:
    return MCPConfiguration()
 
 #endregion: MCP Config
+#region: Project Context (Phase 2 dataclasses for cruft_elimination_20260627)
+
+
+@dataclass(frozen=True, slots=True)
+class ProjectMeta:
+ name:           str  = ""
+ summary_only:   bool = False
+ execution_mode: str  = "standard"
+
+
+@dataclass(frozen=True, slots=True)
+class ProjectOutput:
+ namespace:  str = "project"
+ output_dir: str = ""
+
+
+@dataclass(frozen=True, slots=True)
+class ProjectFiles:
+ base_dir: str           = ""
+ paths:    tuple[str, ...] = ()
+
+
+@dataclass(frozen=True, slots=True)
+class ProjectScreenshots:
+ base_dir: str           = "."
+ paths:    tuple[str, ...] = ()
+
+
+@dataclass(frozen=True, slots=True)
+class ProjectDiscussion:
+ roles:   tuple[str, ...] = ()
+ history: tuple[str, ...] = ()
+
+
+@dataclass(frozen=True, slots=True)
+class ProjectContext:
+ """Typed return type for project_manager.flat_config().
+ Replaces the dict[str, Any] that flat_config() returned.
+ Per conductor/tracks/cruft_elimination_20260627/SPEC_CORRECTION_phase_2.md."""
+ project:         ProjectMeta        = field(default_factory=ProjectMeta)
+ output:          ProjectOutput      = field(default_factory=ProjectOutput)
+ files:           ProjectFiles       = field(default_factory=ProjectFiles)
+ screenshots:     ProjectScreenshots = field(default_factory=ProjectScreenshots)
+ context_presets: Metadata           = field(default_factory=dict)
+ discussion:      ProjectDiscussion  = field(default_factory=ProjectDiscussion)
+
+ def to_dict(self) -> Metadata:
+  return {
+   "project": {
+    "name":           self.project.name,
+    "summary_only":   self.project.summary_only,
+    "execution_mode": self.project.execution_mode,
+   },
+   "output": {
+    "namespace":  self.output.namespace,
+    "output_dir": self.output.output_dir,
+   },
+   "files": {
+    "base_dir": self.files.base_dir,
+    "paths":    list(self.files.paths),
+   },
+   "screenshots": {
+    "base_dir": self.screenshots.base_dir,
+    "paths":    list(self.screenshots.paths),
+   },
+   "context_presets": dict(self.context_presets),
+   "discussion": {
+    "roles":   list(self.discussion.roles),
+    "history": list(self.discussion.history),
+   },
+  }
+
+ def __getitem__(self, key: str) -> Any:
+  return self.to_dict()[key]
+
+ def get(self, key: str, default: Any = None) -> Any:
+  return self.to_dict().get(key, default)
+
+
+EMPTY_PROJECT_CONTEXT: ProjectContext = ProjectContext()
+
+
+#endregion: Project Context