Make pass contracts cover the passes DeepCompile actually schedules; Renaming files

[pengdurice]

[DeepCompile] Make pass contracts cover the passes DeepCompile actually schedules

Follow-up to #8139. Three gaps kept PassContract from firing on real schedules:

1. conflicts_with was ignored whenever the other pass had no registered contract.
2. Only four pass modules were registered, so offload_parameters and the ZeRO-1/2 reduce passes
   could not be validated at all.
3. The one incompatibility DeepSpeed enforces — one offload target per run — was checked inside
   if schedule is None: in init_z3.py, so a user-supplied schedule combining both was accepted.

The conflict fix

validate_schedule matches conflicts against applied, but an uncontracted pass hit continue
before applied.append(name), so a conflict naming it was missed in both orderings. Resolving a
missing contract to a shared empty one instead of branching around it fixes that and removes two
lines of control flow:

contract = _pass_contracts.get(name, _UNCONSTRAINED)

The pass stays unconstrained; it is simply visible to conflicts others declare. test_conflict_is_symmetric
missed this because it registers the second pass with an empty contract, which still lands in the registry.

Contracts

Registered name	Callable	Contract
zero1_compile	add_z1_reduce	conflicts with zero3_compile
zero2_compile	add_z2_reduce	conflicts with zero3_compile, zero1_compile
offload_parameters	offload_parameter_fwd	requires z3_gather_release
offload_adam_states	move_opt_states	requires opt_states_evicted, conflicts with the three below
offload_adam_states_sync	move_opt_states_sync	conflicts with the three below, and offload_adam_states
offload_adam_states_for_init	offload_adam_states_for_init	provides opt_states_evicted, conflicts with the three below

The three shared conflicts are offload_parameters, zero1_compile, zero2_compile.

• offload_parameter_fwd rewrites the dc.allgather_param nodes zero3_compile inserts; without
  it the pass silently matches nothing.
• The optimizer-state passes dereference a module global set only from init_z3.py, so naming one
  in a ZeRO-1/2 schedule validates today and then dies on None.
• opt_states_evicted records a dependency previously implicit in schedule order: move_opt_states
  plans from profiled peaks, which only describe the run once offload_adam_states_for_init has
  taken the optimizer state off the accelerator. move_opt_states_sync reads neither
  profiling_results nor mem_budget and so takes no such requirement.

Conflicts are declared on one side only, which the fix above is what makes reliable.

Naming

Two modules serve stages 1 and 2 but were named for stage 1, matching neither
deepspeed/runtime/zero/stage_1_and_2.py nor the zero2_compile registration:
zero1_compile.py → zero_1_and_2_compile.py, and init_z1.py → init_z1_and_2.py
(init_z1() → init_z1_and_2()). Pure renames, recorded by git as such. Constants become
NAME_Z1 / CONTRACT_Z1 beside the existing _Z2 pair; registered names stay per-stage.

Testing

tests/unit/compile/test_pass_contract.py, 11 tests to 20, all CPU-only. Covers the conflict fix
in both orderings, each new rejection, schedules written with callables rather than names, and that
every schedule init_z1_and_2 and init_z3 build still validates. One guard test asserts every
name in a built-in conflicts_with is itself registered, since those are string literals.

BUILTIN_PASSES mirrors the engine's registration block by hand — reaching the real one needs a
constructed engine — so a pass added to the engine and not the test would go untested.

Compatibility

Registering the remaining passes widens what a schedule may name and narrows nothing. The new
conflicts reject only combinations that already failed at runtime, later and less legibly.

One change genuinely narrows: move_opt_states without offload_adam_states_for_init is now a
PassContractError where it previously ran. Such a run did not fail outright — it planned its
offloading from peaks inflated by the resident optimizer state. Turning that into a schedule-time
error is the intent, but it is the one thing here that rejects something that used to execute.