ci: pass keypair content (not path) to devnet release actions

[dev-jodee]

Summary

• Fixes Write program buffer failing in the release workflow with Input must be a JSON array.
• Pass ${{ env.DEPLOYER_KEYPAIR }} (Doppler-injected content) to the devnet sub-actions instead of the file path /tmp/deployer.json.

Root Cause

The solana-developers/github-actions/{write-program-buffer, program-upgrade, metadata-upload, verify-build} actions all internally do:

- name: Write keypair
  run: echo "$DEPLOY_KEYPAIR" > ./deploy-keypair.json
  env:
    DEPLOY_KEYPAIR: ${{ inputs.keypair }}

i.e. they treat inputs.keypair as the keypair content, not a file path. We were passing /tmp/deployer.json, so the action wrote the literal string /tmp/deployer.json into ./deploy-keypair.json and solana program write-buffer rejected it.

Scope

• Devnet path only (lines 76, 91, 99, 110).
• Mainnet/Squads steps (lines 127, 139, 157) and the Materialize deployer keypair step are intentionally left in place — they will be migrated when next exercised on a real mainnet release.

Test Plan

• Trigger Release workflow against devnet from this branch.
• Confirm Write program buffer, Upgrade program (devnet), Upload IDL via program-metadata (devnet), Verify build (devnet) all succeed.

Failing run for reference: https://github.com/solana-program/subscriptions/actions/runs/25178912188

[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	1805	2118	2003	0.000005000	0.000005080	0.000006001
close_subscription_authority	7	1881	1916	1886	0.000005000	0.000005075	0.000005943
create_fixed_delegation	38	3616	11149	4953	0.000005001	0.000005198	0.000007476
create_plan	84	3540	21553	5221	0.000005001	0.000005208	0.000007610
create_recurring_delegation	27	3640	12673	5257	0.000005001	0.000005210	0.000007628
delete_plan	8	416	416	416	0.000005000	0.000005016	0.000005208
init_subscription_authority	142	7849	28851	12744	0.000005003	0.000005509	0.000011372
revoke_delegation	19	318	585	420	0.000005000	0.000005016	0.000005210
subscribe	21	6666	14166	8533	0.000005002	0.000005341	0.000009266
transfer_fixed	6	10105	19102	13104	0.000005003	0.000005524	0.000011552
transfer_recurring	17	10212	20803	12273	0.000005003	0.000005490	0.000011136
transfer_subscription	10	10446	13495	11250	0.000005003	0.000005450	0.000010625
update_plan	21	424	500	474	0.000005000	0.000005018	0.000005237

Generated: 2026-04-30