Measured post-2050 input anchors and PNG review artifacts for the TD2 SDL port

The current TD2 SDL runtime already had scripted input and a first menu handoff mutator, but it still flattened the post-2050 default-rival corridor into a mostly generic rail.

This checkpoint moves one step deeper into a SNES-mimetic path:

• promoted exact no-input scheduler anchors at frames 2052, 2053, 2083, 2104, and 2125
  


• overlaid the traced default-rival A route on top of those anchors


• carried measured fields instead of heuristics: state_09a2, state_09a8, state_137c, dp_0020, dp_0022, dp_0053, and dp_0054
  


• taught the runtime dump path to emit PNG siblings for every PPM artifact, including compare outputs

The useful practical effect is twofold.

First, the port now has a grounded post-2050 mutation surface that is tied directly to probe evidence instead of broad guessed gameplay logic. Second, the same runtime artifacts that validate the port are now immediately usable by design review without manual conversion.

Validation stayed bounded and green:

• make -C port test


• PNG sanity check against the existing PPM dump path: 0 mismatched pixels on the frame-300 smoke


• local review pack exported for the new anchor frames under tools/out/port_input_mutation_anchor_pngs_20260401/
  

This is still not a full continuous gameplay model. The next step is to densify these exact anchors into short windows, especially around the 2054..2088 dashboard/radar divergence, and then feed live SDL input into the same mutator surface.