Simplify CipherStick by removing the legacy wallet and Sparrow runtime #201

Problem

The custom bails-wallet and optional wallet coordinators make this repository broader and harder to review than the supported installer needs to be. They also carry two concrete maintenance/security failures that disappear when the unsupported runtime is removed:

• Legacy GTK3 Codex32 wallet GUI loops on current Tails #214: the legacy GTK3/Python wallet flow loops on current Tails because it depends on obsolete Python/GTK integration details;
• Bind Sparrow package verification to its publisher key #205: the Sparrow installer does not bind package verification to the expected publisher fingerprint.

Maintaining separate fixes for those obsolete paths would increase trusted code and long-term maintenance cost without improving the intended supported product.

Scope

• Remove the custom bails-wallet application and its bundled wallet/key-handling/codex32 implementation.
• Remove Sparrow and any other third-party wallet-coordinator installer from the supported runtime.
• Retain a narrow CipherStick installer for Tails and Bitcoin Core, plus Persistent Storage passphrase practice/spaced repetition.
• Keep replacement codex32 wallet functionality in python-codex32 and integrate its reviewed GUI separately under Restore Bitcoin Core master seeds from codex32 with python-codex32 #215.
• Preserve recovery guidance for data created by the removed wallet.
• Purge or disable obsolete launchers/integration so current stable Tails cannot fall back into the removed GTK3 flow.
• Preserve user data needed for recovery; removal of managed runtime files must not silently delete unrelated wallet data.

Acceptance criteria

• CipherStick no longer owns wallet creation or private-key handling.
• CipherStick does not install Sparrow, Bisq, Liana, Wasabi, or a generic wallet coordinator.
• The legacy GTK3 wallet/passphrase loop from Legacy GTK3 Codex32 wallet GUI loops on current Tails #214 cannot be entered on current stable Tails.
• The Sparrow package-verification boundary from Bind Sparrow package verification to its publisher key #205 is removed with the unsupported installer instead of maintaining another verification implementation.
• Persistent Storage passphrase practice remains supported independently of the removed wallet GUI.
• The remaining runtime is installer-focused around Tails and Bitcoin Core.
• Existing users have recovery guidance for state created by the removed wallet.
• Replacement codex32 functionality remains a separately reviewed dependency/integration.

PR #202 is the implementation vehicle and already covers the combined scope previously split across #201, #205, and #214.