docs: update README

[JuArce]

No description provided.

[github-actions]

Codex Code Review

No actionable security, correctness, performance, or simplicity issues found in the specified PR diff.

[claude]

Review

Docs-only PR (README + Makefile + config), no contract/application logic changes. Verified cross-references and they're internally consistent:

• config.base-mainnet.json matches the /script-config/config.<name>.json path pattern read by DeployClaimableAirdrop.s.sol.
• tokenProxy in config.mainnet.json (0x50614CC8e44F7814549c223aA31db9296e58057c) and the new config.base-mainnet.json (0x53f39e5C53EE40bbc3Da97C3B47BD2968d110a8D) match the canonical addresses in base/README.md's "Deployed Addresses" table (case differences only, same address).
• L1_BRIDGE_MAINNET address quoted in the new "From a safe" section (0x3154Cf16ccdb4C6d922629664174b904d80F2C35) matches base/.env.example.
• deploy-token-mainnet/deploy-claimable-mainnet/new deploy-claimable-base-mainnet consistently switch from --keystore $(KEYSTORE_PATH) to --interactive, and KEYSTORE_PATH is fully removed (no dangling references left).
• calldata-approve-spending now takes $(APPROVE_AMOUNT) instead of a hardcoded value; the variable already has a sane default (2600000000000000000000000000) defined earlier in the Makefile, so existing invocations without the override keep working.

No security, correctness, or performance issues found — this is a straightforward, well cross-checked documentation update for the Base mainnet claim flow.

Minor nit (non-blocking): the Makefile diff introduces a doubled blank line between the new deploy-claimable-base-mainnet target and the TODO comment below it.