R3 F6 — derive_op_effect typed HttpMethod/Path consumption (Class C; PB v2-retirement coord)

[briansrls]

Auto-opened by session-dashboard for session sharp-lark-82.
Pushing to session/sharp-lark-82 advances this PR.

Closes #2470

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[briansrls]

Closing duplicate session PR: #2490 is the canonical F6 receipt path for gunbc#2470 (same scope — dsl/std/effects.dag typed `derive_op_effect`, v2 bridge/stage0, v3 std + fixtures). Aligns with tidy-ram-461 coordination on gunbc#2470 (duplicate #2489 retired for #2490). No further implementation work tracked here.