refactor(examples): drop 139 try/except guards that could never fire

[TMHSDigital]

Closes #405.

Change

A scripted transform unwraps two shapes in 129 examples/ and showcase/ scripts:

• try: <stmt> / except (AttributeError|KeyError|Exception): pass, single-line and multi-line forms;
• only when <stmt> touches taa_render_samples or one of the input names Coat Weight, Specular IOR Level, Subsurface Weight or Detail Roughness.

That is 139 guards in total: 114 taa_render_samples plus 9 KeyError blocks, with the remainder in single-line forms. Every edited file ast.parses. No other try/except was touched.

Evidence

Probe, live (--factory-startup; binaries report 4.5.11 LTS, 5.1.2, 5.2.1 LTS):

• scene.eevee.taa_render_samples = 64 succeeds under that version's EEVEE id and under Cycles.
• Principled BSDF has Coat Weight, Specular IOR Level and Subsurface Weight on all three versions; Wave texture has Detail Roughness.

So none of the guards could ever fire on a supported version.

Scripts whose former KeyError guards were edited, check path on 5.2.1 and 4.5.11. All exit 0:

• gn-sdf-remesh
• grease-pencil-rosette
• pond-edge
• cactus-garden
• palm-tree
• sea-stack-arch
• sawhorse-plank

The showcase material builders run on the check path, so these runs exercised the unguarded lines.

Render paths (--output --engine cycles, 5.2.1):

• gn-sdf-remesh (former guard in render_still): exit 0, still written;
• turntable (one-line taa guard): exit 0, still written.

Validators: check_helper_drift (--strict, variant counts unchanged), check_render_gates, check_engine_id, check_exit_code_readme, check_witnesses and check_falsifier_targets all pass. CI smoke runs every check path on 5.2 and 4.5.

Not run: the render paths of the other ~110 scripts. Their only change is an attribute assignment proven to exist on all three versions.

🤖 Generated with Claude Code

[TMHSDigital]

CI evidence before merge: all checks pass ( 13 pass ). Blender Smoke on PR head: Blender 5.2.2 LTS / Blender 4.5.14 LTS. Summaries (happy path; falsifiers) per leg: 141 passed, 3 skipped, 0 failed;136 passed, 7 skipped, 0 failed;143 passed, 1 skipped, 0 failed;143 passed, 0 skipped, 0 failed;