refactor: move subscriptions idl to root

[dev-jodee]

Summary

• Move the generated subscriptions IDL from program/idl/ to root idl/ while keeping the subscriptions.json filename.
• Update build.rs, justfile, client generation, webapp aliases, and IDL-based tests to use the root IDL path.
• Update docs for the new IDL location.

Test Plan

• pnpm run generate-idl
• pnpm run generate-clients
• pnpm --filter @subscriptions/client build
• just build-program
• just test-program
• just check
• rg --hidden -n "program/idl|programs/subscriptions/idl" .github README.md CLAUDE.md justfile scripts program webapp Cargo.toml package.json pnpm-workspace.yaml

[github-actions]

Compute Unit Report

Instruction	Samples	Min CUs	Max CUs	Avg CUs	Est Cost (Low) [SOL]	Est Cost (Med) [SOL]	Est Cost (High) [SOL]
cancel_subscription	11	1774	2098	1982	0.000005000	0.000005079	0.000005991
close_subscription_authority	7	1866	1901	1871	0.000005000	0.000005074	0.000005935
create_fixed_delegation	38	3601	12606	5096	0.000005001	0.000005203	0.000007548
create_plan	84	3525	11038	5010	0.000005001	0.000005200	0.000007505
create_recurring_delegation	27	3628	21630	5854	0.000005001	0.000005234	0.000007927
delete_plan	8	401	401	401	0.000005000	0.000005016	0.000005200
init_subscription_authority	142	9334	22837	12529	0.000005003	0.000005501	0.000011264
revoke_delegation	19	303	570	405	0.000005000	0.000005016	0.000005202
subscribe	21	6639	9663	7435	0.000005002	0.000005297	0.000008717
transfer_fixed	6	10063	13066	10815	0.000005003	0.000005432	0.000010407
transfer_recurring	17	10175	13266	11623	0.000005003	0.000005464	0.000010811
transfer_subscription	10	10442	19533	13899	0.000005004	0.000005555	0.000011949
update_plan	21	409	488	461	0.000005000	0.000005018	0.000005230

Generated: 2026-04-29